9befa53ac2
svn path=/trunk/; revision=7165
1470 lines
65 KiB
Text
1470 lines
65 KiB
Text
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The Ethereal FAQ
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Note: This is just an ASCII snapshot of the faq and may not be up to
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date. Please go to http://www.ethereal.com/faq for the up to
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date version. The version of this snapshot can be found at the
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end of this document.
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INDEX
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General Questions:
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1.1 Where can I get help?
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1.2 What protocols are currently supported?
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1.3 Are there any plans to support {your favorite protocol}?
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1.4 Can Ethereal read capture files from {your favorite network
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analyzer}?
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1.5 What devices can Ethereal use to capture packets?
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1.6 How do you pronounce Ethereal? Where did the name come from?
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Downloading Ethereal:
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2.1 I downloaded the Win32 installer, but when I try to run it, I get
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an error.
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2.2 When I try to download the WinPcap driver and library, I can't get
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to the WinPcap Web site.
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Installing Ethereal:
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3.1 I installed an Ethereal RPM, but Ethereal doesn't seem to be
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installed; only Tethereal is installed.
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Building Ethereal:
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4.1 The configure script can't find pcap.h or bpf.h, but I have
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libpcap installed.
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4.2 Why do I get the error
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dftest_DEPENDENCIES was already defined in condition TRUE, which
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implies condition HAVE_PLUGINS_TRUE
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when I try to build Ethereal from CVS or a CVS snapshot?
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4.3 The link failed because of an undefined reference to
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snmp_set_full_objid.
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4.4 The link fails with a number of "Output line too long." messages
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followed by linker errors.
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4.5 The link fails on Solaris because plugin_list is undefined.
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4.6 The build fails on Windows because of conflicts between winsock.h
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and winsock2.h.
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Using Ethereal:
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5.1 When I use Ethereal to capture packets, I see only packets to and
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from my machine, or I'm not seeing all the traffic I'm expecting to
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see from or to the machine I'm trying to monitor.
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5.2 I can't see any TCP packets other than packets to and from my
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machine, even though another sniffer on the network sees those
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packets.
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5.3 I can set a display filter just fine, but capture filters don't
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work.
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5.4 I'm entering valid capture filters, but I still get "parse error"
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errors.
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5.5 I saved a filter and tried to use its name to filter the display,
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but I got an "Unexpected end of filter string" error.
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5.6 I've just installed Ethereal, and the traffic on my local LAN is
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boring.
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5.7 When I run Ethereal on Solaris 8, it dies with a Bus Error when I
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start it.
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5.8 I'm running Ethereal on Linux; why do my time stamps have only
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100ms resolution, rather than 1us resolution?
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5.9 I'm capturing packets on {Windows 95, Windows 98, Windows Me}; why
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are the time stamps on packets wrong?
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5.10 When I try to run Ethereal on Windows, it fails to run because it
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can't find packet.dll.
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5.11 Why does some network interface on my machine not show up in the
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list of interfaces in the "Interface:" field in the dialog box popped
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up by "Capture->Start", and/or why does Ethereal give me an error if I
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try to capture on that interface?
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5.12 I'm running Ethereal on Windows NT/2000/XP/Server; my machine has
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a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
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"Interface" item in the "Capture Options" dialog box. Why can no
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packets be sent on or received from that network while I'm trying to
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capture traffic on that interface?
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5.13 I'm running Ethereal on Windows 95/98/Me, on a machine with more
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than one network adapter of the same type; Ethereal shows all of those
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adapters with the same name, but I can't use any of those adapters
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other than the first one.
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5.14 I have an XXX network card on my machine; if I try to capture on
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it, my machine crashes or resets itself.
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5.15 My machine crashes or resets itself when I select "Start" from
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the "Capture" menu or select "Preferences" from the "Edit" menu.
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5.16 Does Ethereal work on Windows ME?
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5.17 Does Ethereal work on Windows XP?
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5.18 Why doesn't Ethereal correctly identify RTP packets? It shows
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them only as UDP.
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5.19 Why doesn't Ethereal show Yahoo Messenger packets in captures
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that contain Yahoo Messenger traffic?
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5.20 Why do I get the error
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Gdk-ERROR **: Palettized display (256-colour) mode not supported on
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Windows.
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aborting....
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when I try to run Ethereal on Windows?
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5.21 When I capture on Windows in promiscuous mode, I can see packets
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other than those sent to or from my machine; however, those packets
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show up with a "Short Frame" indication, unlike packets to or from my
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machine. What should I do to arrange that I see those packets in their
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entirety?
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5.22 How can I capture raw 802.11 packets, including non-data
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(management, beacon) packets?
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5.23 How can I capture packets with CRC errors?
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5.24 How can I capture entire frames, including the FCS?
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5.25 Ethereal hangs after I stop a capture.
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5.26 How can I search for, or filter, packets that have a particular
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string anywhere in them?
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GENERAL QUESTIONS
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Q 1.1: Where can I get help?
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A: Support is available on the ethereal-users mailing list.
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Subscription information and archives for all of Ethereal's mailing
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lists can be found at http://www.ethereal.com/lists
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Q 1.2: What protocols are currently supported?
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A: There are currently 355 supported protocols and media, listed
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below. Descriptions can be found in the ethereal(1) man page.
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802.1q Virtual LAN
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802.1x Authentication
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Address Resolution Protocol
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Ad hoc On-demand Distance Vector Routing Protocol
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Ad hoc On-demand Distance Vector Routing Protocol v6
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AFS (4.0) Replication Server call declarations
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Aggregate Server Access Protocol
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Andrew File System (AFS)
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AOL Instant Messenger
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Apache JServ Protocol v1.3
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Appletalk Address Resolution Protocol
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AppleTalk Filing Protocol
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AppleTalk Session Protocol
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AppleTalk Transaction Protocol packet
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ARCNET
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Async data over ISDN (V.120)
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ATM
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ATM AAL1
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ATM AAL3/4
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ATM LAN Emulation
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ATM OAM AAL
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Authentication Header
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AVS WLAN Capture header
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BACnet Virtual Link Control
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Banyan Vines
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Banyan Vines Fragmentation Protocol
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Banyan Vines SPP
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Blocks Extensible Exchange Protocol
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Boardwalk
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Boot Parameters
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Bootstrap Protocol
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Border Gateway Protocol
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Building Automation and Control Network APDU
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Building Automation and Control Network NPDU
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CDS Clerk Server Calls
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Checkpoint FW-1
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Check Point High Availability Protocol
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Cisco Auto-RP
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Cisco Discovery Protocol
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Cisco Group Management Protocol
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Cisco HDLC
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Cisco Hot Standby Router Protocol
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Cisco Interior Gateway Routing Protocol
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Cisco ISL
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Cisco NetFlow
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Cisco SLARP
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Clearcase NFS
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Common Open Policy Service
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Common Unix Printing System (CUPS) Browsing Protocol
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CoSine IPNOS L2 debug output
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Data
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Datagram Delivery Protocol
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Data Link SWitching
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Data Stream Interface
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DCE DFS Calls
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DCE Distributed Time Service Local Server
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DCE Distributed Time Service Provider
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DCE Name Service
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DCE RPC
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DCE/RPC BOS Server
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DCE/RPC CDS Solicitation
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DCE/RPC Conversation Manager
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DCE/RPC Endpoint Mapper
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DCE/RPC FLDB
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DCE/RPC FLDB UBIK TRANSFER
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DCE/RPC FLDB UBIKVOTE
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DCE/RPC Kerberos V
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DCE/RPC Remote Management
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DCE/RPC Repserver Calls
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DCE/RPC RS_ACCT
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DCE/RPC RS_MISC
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DCE/RPC RS_UNIX
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DCE/RPC TokenServer Calls
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DCE/RPC UpServer
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DCE Security ID Mapper
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DCOM OXID Resolver
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DCOM Remote Activation
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DEC Spanning Tree Protocol
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DHCPv6
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Diameter Protocol
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Distance Vector Multicast Routing Protocol
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Distributed Checksum Clearinghouse Prototocl
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DNS Control Program Server
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Domain Name Service
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Dummy Protocol
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Dynamic DNS Tools Protocol
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Encapsulating Security Payload
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Enhanced Interior Gateway Routing Protocol
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Ethernet
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Extensible Authentication Protocol
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FC Extended Link Svc
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FC Fabric Configuration Server
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FCIP
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Fiber Distributed Data Interface
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Fibre Channel
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Fibre Channel Common Transport
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Fibre Channel Fabric Zone Server
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Fibre Channel Name Server
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Fibre Channel Protocol for SCSI
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Fibre Channel SW_ILS
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File Transfer Protocol (FTP)
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Financial Information eXchange Protocol
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Frame
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Frame Relay
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FTP Data
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FTServer Operations
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GARP Multicast Registration Protocol
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GARP VLAN Registration Protocol
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General Inter-ORB Protocol
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Generic Routing Encapsulation
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Generic Security Service Application Program Interface
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Gnutella Protocol
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GPRS Tunneling Protocol
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GPRS Tunnelling Protocol v0
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GPRS Tunnelling Protocol v1
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Hummingbird NFS Daemon
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HyperSCSI
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Hypertext Transfer Protocol
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ICQ Protocol
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IEEE 802.11 wireless LAN
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IEEE 802.11 wireless LAN management frame
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ILMI
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Inter-Access-Point Protocol
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Interbase
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Internet Cache Protocol
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Internet Content Adaptation Protocol
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Internet Control Message Protocol
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Internet Control Message Protocol v6
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Internet Group Management Protocol
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Internet Message Access Protocol
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Internet Printing Protocol
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Internet Protocol
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Internet Protocol Version 6
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Internet Relay Chat
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Internet Security Association and Key Management Protocol
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Internetwork Packet eXchange
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IP Over FC
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IP Payload Compression
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IPX Message
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IPX Routing Information Protocol
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iSCSI
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ISDN
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ISDN Q.921-User Adaptation Layer
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ISDN User Part
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ISO 10589 ISIS InTRA Domain Routeing Information Exchange Protocol
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ISO 8073 COTP Connection-Oriented Transport Protocol
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ISO 8473 CLNP ConnectionLess Network Protocol
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ISO 8602 CLTP ConnectionLess Transport Protocol
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ISO 9542 ESIS Routeing Information Exchange Protocol
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ITU-T Recommendation H.261
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Java RMI
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Java Serialization
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Kerberos
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Kernel Lock Manager
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Label Distribution Protocol
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Layer 2 Tunneling Protocol
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Lightweight Directory Access Protocol
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Line Printer Daemon Protocol
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Link Access Procedure Balanced Ethernet (LAPBETHER)
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Link Access Procedure Balanced (LAPB)
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Link Access Procedure, Channel D (LAPD)
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Link Aggregation Control Protocol
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Link Management Protocol (LMP)
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Linux cooked-mode capture
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Local Management Interface
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LocalTalk Link Access Protocol
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Logical-Link Control
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Lucent/Ascend debug output
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MDS Header
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Message Transfer Part Level 2
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Message Transfer Part Level 3
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Message Transfer Part Level 3 Management
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Microsoft Distributed File System
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Microsoft Exchange MAPI
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Microsoft Local Security Architecture
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Microsoft Local Security Architecture (Directory Services)
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Microsoft Network Logon
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Microsoft Registry
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Microsoft Security Account Manager
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Microsoft Server Service
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Microsoft Spool Subsystem
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Microsoft Telephony API Service
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Microsoft Windows Browser Protocol
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Microsoft Windows Lanman Remote API Protocol
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Microsoft Windows Logon Protocol
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Microsoft Workstation Service
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MMS Message Encapsulation
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Mobile IP
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Modbus/TCP
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Mount Service
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MSNIP: Multicast Source Notification of Interest Protocol
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MS Proxy Protocol
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MTP2 Peer Adaptation Layer
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MTP 2 Transparent Proxy
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MTP 2 User Adaptation Layer
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MTP 3 User Adaptation Layer
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Multicast Router DISCovery protocol
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Multicast Source Discovery Protocol
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MultiProtocol Label Switching Header
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MySQL Protocol
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Name Binding Protocol
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Name Management Protocol over IPX
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NetBIOS
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NetBIOS Datagram Service
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NetBIOS Name Service
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NetBIOS over IPX
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NetBIOS Session Service
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NetWare Core Protocol
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Network Data Management Protocol
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Network File System
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Network Lock Manager Protocol
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Network News Transfer Protocol
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Network Status Monitor CallBack Protocol
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Network Status Monitor Protocol
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Network Time Protocol
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NFSACL
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NFSAUTH
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NIS+
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NIS+ Callback
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Novell Distributed Print System
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NSPI
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NTLM Secure Service Provider
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Null/Loopback
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OpenBSD Packet Filter log file
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Open Shortest Path First
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PC NFS
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Point-to-Point Protocol
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Point-to-Point Tunnelling Protocol
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Portmap
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Post Office Protocol
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PPP Bandwidth Allocation Control Protocol
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PPP Bandwidth Allocation Protocol
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PPP Callback Control Protocol
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PPP CDP Control Protocol
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PPP Challenge Handshake Authentication Protocol
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PPP Compressed Datagram
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PPP Compression Control Protocol
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PPP IP Control Protocol
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PPP IPv6 Control Protocol
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PPP Link Control Protocol
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PPP MPLS Control Protocol
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PPP Multilink Protocol
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PPP Multiplexing
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PPPMux Control Protocol
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PPP-over-Ethernet Discovery
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PPP-over-Ethernet Session
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PPP Password Authentication Protocol
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PPP VJ Compression
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Pragmatic General Multicast
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Prism
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Privilege Server operations
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Protocol Independent Multicast
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Q.2931
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Q.931
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Quake III Arena Network Protocol
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Quake II Network Protocol
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Quake Network Protocol
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QuakeWorld Network Protocol
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Qualified Logical Link Control
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Radio Access Network Application Part
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Radius Protocol
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Raw packet data
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Real Time Streaming Protocol
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Real-time Transport Control Protocol
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Real-Time Transport Protocol
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Registry server administration operations.
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Registry Server Attributes Manipulation Interface
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Remote Override interface
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Remote Procedure Call
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Remote Program Load
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Remote Quota
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Remote sec_login preauth interface.
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Remote Shell
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Remote Wall protocol
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Resource ReserVation Protocol (RSVP)
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RFC 2250 MPEG1
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RIPng
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Rlogin Protocol
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Routing Information Protocol
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Routing Table Maintenance Protocol
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RPC Browser
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RSTAT
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RX Protocol
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SADMIND
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SCSI
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Secure Socket Layer
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Sequenced Packet eXchange
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Service Advertisement Protocol
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Service Location Protocol
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Session Announcement Protocol
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Session Description Protocol
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Session Initiation Protocol
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SGI Mount Service
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Short Message Peer to Peer
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Signalling Connection Control Part
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Signalling Connection Control Part Management
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Simple Mail Transfer Protocol
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Simple Network Management Protocol
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Sinec H1 Protocol
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Skinny Client Control Protocol
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SliMP3 Communication Protocol
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SMB MailSlot Protocol
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SMB Pipe Protocol
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SMB (Server Message Block Protocol)
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SNA-over-Ethernet
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SNMP Multiplex Protocol
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Socks Protocol
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Spanning Tree Protocol
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Spnego
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SPNEGO-KRB5
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SPRAY
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SS7 SCCP-User Adaptation Layer
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SSCOP
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Stream Control Transmission Protocol
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Synchronous Data Link Control (SDLC)
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Syslog message
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Systems Network Architecture
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Tabular Data Stream
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TACACS
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TACACS+
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Tazmen Sniffer Protocol
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Telnet
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Time Protocol
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Time Synchronization Protocol
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Token-Ring
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Token-Ring Media Access Control
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TPKT
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Transmission Control Protocol
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Transparent Network Substrate Protocol
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Trivial File Transfer Protocol
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Universal Computer Protocol
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User Datagram Protocol
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Virtual Router Redundancy Protocol
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Virtual Trunking Protocol
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Web Cache Coordination Protocol
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Wellfleet Compression
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Wellfleet HDLC
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Who
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Windows 2000 DNS
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Wireless Session Protocol
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Wireless Transaction Protocol
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Wireless Transport Layer Security
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X11
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X.25
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X.25 over TCP
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X.29
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X Display Manager Control Protocol
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Xyplex
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Yahoo Messenger Protocol
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Yellow Pages Bind
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Yellow Pages Passwd
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Yellow Pages Service
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Yellow Pages Transfer
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Zebra Protocol
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Zone Information Protocol
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Q 1.3: Are there any plans to support {your favorite protocol}?
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A: Support for particular protocols is added to Ethereal as a result
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of people contributing that support; no formal plans for adding
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support for particular protocols in particular future releases exist.
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Q 1.4: Can Ethereal read capture files from {your favorite network
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analyzer}?
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A: Support for particular protocols is added to Ethereal as a result
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of people contributing that support; no formal plans for adding
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support for particular protocols in particular future releases exist.
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If a network analyzer writes out files in a format already supported
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by Ethereal (e.g., in libpcap format), Ethereal may already be able to
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read them, unless the analyzer has added its own proprietary
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extensions to that format.
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If a network analyzer writes out files in its own format, or has added
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proprietary extensions to another format, in order to make Ethereal
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read captures from that network analyzer, we would either have to have
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a specification for the file format, or the extensions, sufficient to
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give us enough information to read the parts of the file relevant to
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Ethereal, or would need at least one capture file in that format AND a
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detailed textual analysis of the packets in that capture file (showing
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packet time stamps, packet lengths, and the top-level packet header)
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in order to reverse-engineer the file format.
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Note that there is no guarantee that we will be able to
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reverse-engineer a capture file format.
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Q 1.5: What devices can Ethereal use to capture packets?
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|
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A: Ethereal can read live data from Ethernet, Token-Ring, FDDI, serial
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(PPP and SLIP) (if the OS on which it's running allows Ethereal to do
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so), 802.11 wireless LAN (if the OS on which it's running allows
|
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Ethereal to do so), ATM connections (if the OS on which it's running
|
|
allows Ethereal to do so), and the "any" device supported on Linux by
|
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recent versions of libpcap. See the list of supported capture media on
|
|
various OSes for details (several items in there say "Unknown", which
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doesn't mean "Ethereal can't capture on them", it means "we don't know
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whether it can capture on them"; we expect that it will be able to
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capture on many of them, but we haven't tried it ourselves - if you
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try one of those types and it works, please send an update to
|
|
ethereal-web[AT]ethereal.com).
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|
It can also read a variety of capture file formats, including:
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* libpcap/tcpdump
|
|
* Sun snoop/atmsnoop
|
|
* Shomiti/Finisar Surveyor
|
|
* LanAlyzer
|
|
* DOS-based Sniffer (compressed and uncompressed)
|
|
* MS Network Monitor
|
|
* AIX iptrace
|
|
* NetXray and Windows-based Sniffer
|
|
* EtherPeek/TokenPeek/AiroPeek
|
|
* RADCOM WAN/LAN analyzer
|
|
* Lucent/Ascend debug output
|
|
* Toshiba ISDN router "snoop" output
|
|
* HPUX nettl
|
|
* ISDN4BSD "i4btrace" utility.
|
|
* Cisco Secure IDS
|
|
* pppd log files (pppdump format)
|
|
* VMS TCPIPtrace
|
|
* DBS Etherwatch
|
|
* Visual Networks' Visual UpTime
|
|
* CoSine L2 debug
|
|
|
|
so that it can read traces from various network types, as captured by
|
|
other applications or equipment, even if it cannot itself capture on
|
|
those network types.
|
|
|
|
Q 1.6: How do you pronounce Ethereal? Where did the name come from?
|
|
|
|
A: The English pronunciation can be found in Merriam-Webster's online
|
|
dictionary at
|
|
http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=ethereal.
|
|
|
|
According to the book "Computer Networks" by Andrew Tannenbaum,
|
|
Ethernet was named after the "luminiferous ether" which was once
|
|
thought to carry electromagnetic radiation. Taking that into
|
|
consideration, Ethereal seemed like an appropriate name for an
|
|
Ethernet sniffer.
|
|
|
|
DOWNLOADING ETHEREAL
|
|
Q 2.1: I downloaded the Win32 installer, but when I try to run it, I
|
|
get an error.
|
|
|
|
A: The program you used to download it may have downloaded it
|
|
incorrectly. Web browsers sometimes may do this.
|
|
|
|
Try downloading it with, for example:
|
|
* Wget, for which Windows binaries are available on the SunSITE FTP
|
|
server at sunsite.tk or Heiko Herold's windows wget spot - wGetGUI
|
|
offers a GUI interface that uses wget;
|
|
* WS_FTP from Ipswitch,
|
|
* the ftp command that comes with Windows.
|
|
|
|
If you use the ftp command, make sure you do the transfer in binary
|
|
mode rather than ASCII mode, by using the binary command before
|
|
transferring the file.
|
|
|
|
Q 2.2: When I try to download the WinPcap driver and library, I can't
|
|
get to the WinPcap Web site.
|
|
|
|
A: As is the case with all Web sites, that site won't necessarily
|
|
always be accessible; the server may be down due to a problem or down
|
|
for maintenance, or there may be a networking problem between you and
|
|
the server. You should try again later, or try the local mirror or the
|
|
Wiretapped.net mirror.
|
|
|
|
INSTALLING ETHEREAL
|
|
Q 3.1: I installed an Ethereal RPM, but Ethereal doesn't seem to be
|
|
installed; only Tethereal is installed.
|
|
|
|
A: Red Hat RPMs for Ethereal put only the non-GUI components into the
|
|
ethereal RPM, the fact that Ethereal is a GUI program nonwithstanding;
|
|
there's a separate ethereal-gnome RPM that includes GUI components
|
|
such as Ethereal itself, the fact that Ethereal doesn't use GNOME
|
|
nonwithstanding. Find the ethereal-gnome RPM, and install that also.
|
|
|
|
BUILDING ETHEREAL
|
|
Q 4.1: The configure script can't find pcap.h or bpf.h, but I have
|
|
libpcap installed.
|
|
|
|
A: Are you sure pcap.h and bpf.h are installed? The official
|
|
distribution of libpcap only installs the libpcap.a library file when
|
|
"make install" is run. To install pcap.h and bpf.h, you must run "make
|
|
install-incl". If you're running Debian or Redhat, make sure you have
|
|
the "libpcap-dev" or "libpcap-devel" packages installed.
|
|
|
|
It's also possible that pcap.h and bpf.h have been installed in a
|
|
strange location. If this is the case, you may have to tweak
|
|
aclocal.m4.
|
|
|
|
Q 4.2: Why do I get the error
|
|
|
|
dftest_DEPENDENCIES was already defined in condition TRUE, which
|
|
implies condition HAVE_PLUGINS_TRUE
|
|
|
|
when I try to build Ethereal from CVS or a CVS snapshot?
|
|
|
|
A: You probably have automake 1.5 installed on your machine (the
|
|
command automake --version will report the version of automake on your
|
|
machine). There is a bug in that version of automake that causes this
|
|
problem; upgrade to a later version of automake (1.6 or later).
|
|
|
|
Q 4.3: The link failed because of an undefined reference to
|
|
snmp_set_full_objid.
|
|
|
|
A: You probably have the shared library for UCD SNMP 4.1.1 installed
|
|
(so that snmp_set_full_objid is a macro, rather than a routine in the
|
|
SNMP shared library), but the `development' package for an earlier or
|
|
later UCD SNMP library (so that snmp_set_full_objid is not defined as
|
|
a macro, causing Ethereal to attempt to call it as a routine).
|
|
|
|
If you are on a Linux system that uses RPMs, and the UCD SNMP packages
|
|
are installed as RPMs, the command rpm -qa | grep snmp will report the
|
|
versions of the SNMP packages you have installed; they should all have
|
|
the same version number, such as 4.0.1 or 4.1.1 or 4.1.2. If they
|
|
don't, remove the RPM for the development package (which will probably
|
|
have a name beginning with ucd-snmp-devel) and install the version of
|
|
the development package with the same version number as the other
|
|
ucd-snmp packages have.
|
|
|
|
After installing the 4.1.1 version of the UCD SNMP header files, do a
|
|
make clean and then rebuild Ethereal.
|
|
|
|
Q 4.4: The link fails with a number of "Output line too long."
|
|
messages followed by linker errors.
|
|
|
|
A: The version of the sed command on your system is incapable of
|
|
handling very long lines. On Solaris, for example, /usr/bin/sed has a
|
|
line length limit too low to allow libtool to work; /usr/xpg4/bin/sed
|
|
can handle it, as can GNU sed if you have it installed.
|
|
|
|
On Solaris, changing your command search path to search /usr/xpg4/bin
|
|
before /usr/bin should make the problem go away; on any platform on
|
|
which you have this problem, installing GNU sed and changing your
|
|
command path to search the directory in which it is installed before
|
|
searching the directory with the version of sed that came with the OS
|
|
should make the problem go away.
|
|
|
|
Q 4.5: The link fails on Solaris because plugin_list is undefined.
|
|
|
|
A: This appears to be due to a problem with some versions of the GTK+
|
|
and GLib packages from www.sunfreeware.org; un-install those packages,
|
|
and try getting the 1.2.10 versions from that site, or the versions
|
|
from The Written Word, or the versions from Sun's GNOME distribution,
|
|
or the versions from the supplemental software CD that comes with the
|
|
Solaris media kit, or build them from source from the GTK Web site.
|
|
Then re-run the configuration script, and try rebuilding Ethereal. (If
|
|
you get the 1.2.10 versions from www.sunfreeware.org, and the problem
|
|
persists, un-install them and try installing one of the other versions
|
|
mentioned.)
|
|
|
|
Q 4.6: The build fails on Windows because of conflicts between
|
|
winsock.h and winsock2.h.
|
|
|
|
A: As of Ethereal 0.9.5, you must install WinPcap 2.3 or later, and
|
|
the corresponding version of the developer's pack, in order to be able
|
|
to compile Ethereal; it will not compile with older versions of the
|
|
developer's pack. The symptoms of this failure are conflicts between
|
|
definitions in winsock.h and in winsock2.h; Ethereal uses winsock2.h,
|
|
but pre-2.3 versions of the WinPcap developer's packet use winsock.h.
|
|
(2.3 uses winsock2.h, so if Ethereal were to use winsock.h, it would
|
|
not be able to build with current versions of the WinPcap developer's
|
|
pack.)
|
|
|
|
Note that the installed version of the developer's pack should be the
|
|
same version as the version of WinPcap you have installed.
|
|
|
|
USING ETHEREAL
|
|
Q 5.1: When I use Ethereal to capture packets, I see only packets to
|
|
and from my machine, or I'm not seeing all the traffic I'm expecting
|
|
to see from or to the machine I'm trying to monitor.
|
|
|
|
A: This might be because the interface on which you're capturing is
|
|
plugged into a switch; on a switched network, unicast traffic between
|
|
two ports will not necessarily appear on other ports - only broadcast
|
|
and multicast traffic will be sent to all ports.
|
|
|
|
Note that even if your machine is plugged into a hub, the "hub" may be
|
|
a switched hub, in which case you're still on a switched network.
|
|
|
|
Note also that on the Linksys Web site, they say that their
|
|
auto-sensing hubs "broadcast the 10Mb packets to the port that operate
|
|
at 10Mb only and broadcast the 100Mb packets to the ports that operate
|
|
at 100Mb only", which would indicate that if you sniff on a 10Mb port,
|
|
you will not see traffic coming sent to a 100Mb port, and vice versa.
|
|
This problem has also been reported for Netgear dual-speed hubs, and
|
|
may exist for other "auto-sensing" or "dual-speed" hubs.
|
|
|
|
Some switches have the ability to replicate all traffic on all ports
|
|
to a single port so that you can plug your sniffer into that single
|
|
port to sniff all traffic. You would have to check the documentation
|
|
for the switch to see if this is possible and, if so, to see how to do
|
|
this. See, for example, this documentation from Cisco on the Switched
|
|
Port Analyzer (SPAN) feature on Catalyst switches.
|
|
|
|
Note also that many firewall/NAT boxes have a switch built into them;
|
|
this includes many of the "cable/DSL router" boxes. If you have a box
|
|
of that sort, that has a switch with some number of Ethernet ports
|
|
into which you plug machines on your network, and another Ethernet
|
|
port used to connect to a cable or DSL modem, you can, at least, sniff
|
|
traffic between the machines on your network and the Internet by
|
|
plugging the Ethernet port on the router going to the modem, the
|
|
Ethernet port on the modem, and the machine on which you're running
|
|
Ethereal into a hub (make sure it's not a switching hub, and that, if
|
|
it's a dual-speed hub, all three of those ports are running at the
|
|
same speed.
|
|
|
|
If your machine is not plugged into a switched network or a dual-speed
|
|
hub, or it is plugged into a switched network but the port is set up
|
|
to have all traffic replicated to it, the problem might be that the
|
|
network interface on which you're capturing doesn't support
|
|
"promiscuous" mode, or because your OS can't put the interface into
|
|
promiscuous mode. Normally, network interfaces supply to the host
|
|
only:
|
|
* packets sent to one of that host's link-layer addresses;
|
|
* broadcast packets;
|
|
* multicast packets sent to a multicast address that the host has
|
|
configured the interface to accept.
|
|
|
|
Most network interfaces can also be put in "promiscuous" mode, in
|
|
which they supply to the host all network packets they see. Ethereal
|
|
will try to put the interface on which it's capturing into promiscuous
|
|
mode unless the "Capture packets in promiscuous mode" option is turned
|
|
off in the "Capture Options" dialog box, and Tethereal will try to put
|
|
the interface on which it's capturing into promiscuous mode unless the
|
|
-p option was specified. However, some network interfaces don't
|
|
support promiscuous mode, and some OSes might not allow interfaces to
|
|
be put into promiscuous mode.
|
|
|
|
If the interface is not running in promiscuous mode, it won't see any
|
|
traffic that isn't intended to be seen by your machine. It will see
|
|
broadcast packets, and multicast packets sent to a multicast MAC
|
|
address the interface is set up to receive.
|
|
|
|
You should ask the vendor of your network interface whether it
|
|
supports promiscuous mode. If it does, you should ask whoever supplied
|
|
the driver for the interface (the vendor, or the supplier of the OS
|
|
you're running on your machine) whether it supports promiscuous mode
|
|
with that network interface.
|
|
|
|
In the case of token ring interfaces, the drivers for some of them, on
|
|
Windows, may require you to enable promiscuous mode in order to
|
|
capture in promiscuous mode. Ask the vendor of the card how to do
|
|
this.
|
|
|
|
In the case of wireless LAN interfaces, it appears that, when those
|
|
interfaces are promiscuously sniffing, they're running in a
|
|
significantly different mode from the mode that they run in when
|
|
they're just acting as network interfaces (to the extent that it would
|
|
be a significant effor for those drivers to support for promiscuously
|
|
sniffing and acting as regular network interfaces at the same time),
|
|
so it may be that Windows drivers for those interfaces don't support
|
|
promiscuous mode.
|
|
|
|
Q 5.2: I can't see any TCP packets other than packets to and from my
|
|
machine, even though another sniffer on the network sees those
|
|
packets.
|
|
|
|
A: You're probably not seeing any packets other than unicast packets
|
|
to or from your machine, and broadcast and multicast packets; a switch
|
|
will normally send to a port only unicast traffic sent to the MAC
|
|
address for the interface on that port, and broadcast and multicast
|
|
traffic - it won't send to that port unicast traffic sent to a MAC
|
|
address for some other interface - and a network interface not in
|
|
promiscuous mode will receive only unicast traffic sent to the MAC
|
|
address for that interface, broadcast traffic, and multicast traffic
|
|
sent to a multicast MAC address the interface is set up to receive.
|
|
|
|
TCP doesn't use broadcast or multicast, so you will only see your own
|
|
TCP traffic, but UDP services may use broadcast or multicast so you'll
|
|
see some UDP traffic - however, this is not a problem with TCP
|
|
traffic, it's a problem with unicast traffic, as you also won't see
|
|
all UDP traffic between other machines.
|
|
|
|
I.e., this is probably the same problem discussed in the previous
|
|
question; see the response to that question.
|
|
|
|
Q 5.3: I can set a display filter just fine, but capture filters don't
|
|
work.
|
|
|
|
A: Capture filters currently use a different syntax than display
|
|
filters. Here's the corresponding section from the ethereal(1) man
|
|
page:
|
|
|
|
"Display filters in Ethereal are very powerful; more fields are
|
|
filterable in Ethereal than in other protocol analyzers, and the
|
|
syntax you can use to create your filters is richer. As Ethereal
|
|
progresses, expect more and more protocol fields to be allowed in
|
|
display filters.
|
|
|
|
Packet capturing is performed with the pcap library. The capture
|
|
filter syntax follows the rules of the pcap library. This syntax is
|
|
different from the display filter syntax."
|
|
|
|
The capture filter syntax used by libpcap can be found in the
|
|
tcpdump(8) man page.
|
|
|
|
Q 5.4: I'm entering valid capture filters, but I still get "parse
|
|
error" errors.
|
|
|
|
A: There is a bug in some versions of libpcap/WinPcap that cause it to
|
|
report parse errors even for valid expressions if a previous filter
|
|
expression was invalid and got a parse error.
|
|
|
|
Try exiting and restarting Ethereal; if you are using a version of
|
|
libpcap/WinPcap with this bug, this will "erase" its memory of the
|
|
previous parse error. If the capture filter that got the "parse error"
|
|
now works, the earlier error with that filter was probably due to this
|
|
bug. The bug was fixed in libpcap 0.6; 0.4[.x] and 0.5[.x] versions of
|
|
libpcap have this bug, but 0.6[.x] and later versions don't.
|
|
|
|
Versions of WinPcap prior to 2.3 are based on pre-0.6 versions of
|
|
libpcap, and have this bug; WinPcap 2.3 is based on libpcap 0.6.2, and
|
|
doesn't have this bug.
|
|
|
|
If you are running Ethereal on a UNIX-flavored platform, run "ethereal
|
|
-v", or select "About Ethereal..." from the "Help" menu in Ethereal,
|
|
to see what version of libpcap it's using. If it's not 0.6 or later,
|
|
you will need either to upgrade your OS to get a later version of
|
|
libpcap, or will need to build and install a later version of libpcap
|
|
from the tcpdump.org Web site and then recompile Ethereal from source
|
|
with that later version of libpcap.
|
|
|
|
If you are running Ethereal on Windows with a pre-2.3 version of
|
|
WinPcap, you will need to un-install WinPcap and then download and
|
|
install WinPcap 2.3.
|
|
|
|
Q 5.5: I saved a filter and tried to use its name to filter the
|
|
display, but I got an "Unexpected end of filter string" error.
|
|
|
|
A: You cannot use the name of a saved display filter as a filter. To
|
|
filter the display, you can enter a display filter expression - not
|
|
the name of a saved display filter - in the "Filter:" box at the
|
|
bottom of the display, and type the key or press the "Apply" button
|
|
(that does not require you to have a saved filter), or, if you want to
|
|
use a saved filter, you can press the "Filter:" button, select the
|
|
filter in the dialog box that pops up, and press the "OK" button.
|
|
|
|
Q 5.6: I've just installed Ethereal, and the traffic on my local LAN
|
|
is boring.
|
|
|
|
A: We have a collection of strange and exotic sample capture files at
|
|
http://www.ethereal.com/sample/
|
|
|
|
Q 5.7: When I run Ethereal on Solaris 8, it dies with a Bus Error when
|
|
I start it.
|
|
|
|
A: Some versions of the GTK+ library from www.sunfreeware.org appear
|
|
to be buggy, causing Ethereal to drop core with a Bus Error.
|
|
Un-install those packages, and try getting the 1.2.10 version from
|
|
that site, or the version from The Written Word, or the version from
|
|
Sun's GNOME distribution, or the version from the supplemental
|
|
software CD that comes with the Solaris media kit, or build it from
|
|
source from the GTK Web site. Update the GLib library to the 1.2.10
|
|
version, from the same source, as well. (If you get the 1.2.10
|
|
versions from www.sunfreeware.org, and the problem persists,
|
|
un-install them and try installing one of the other versions
|
|
mentioned.) Similar problems may exist with older versions of GTK+ for
|
|
earlier versions of Solaris.
|
|
|
|
Q 5.8: I'm running Ethereal on Linux; why do my time stamps have only
|
|
100ms resolution, rather than 1us resolution?
|
|
|
|
A: Ethereal gets time stamps from libpcap/WinPcap, and libpcap/WinPcap
|
|
get them from the OS kernel, so Ethereal - and any other program using
|
|
libpcap, such as tcpdump - is at the mercy of the time stamping code
|
|
in the OS for time stamps.
|
|
|
|
At least on x86-based machines, Linux can get high-resolution time
|
|
stamps on newer processors with the Time Stamp Counter (TSC) register;
|
|
for example, Intel x86 processors, starting with the Pentium Pro, and
|
|
including all x86 processors since then, have had a TSC, and other
|
|
vendors probably added the TSC at some point to their families of x86
|
|
processors.
|
|
|
|
The Linux kernel must be configured with the CONFIG_X86_TSC option
|
|
enabled in order to use the TSC. Make sure this option is enabled in
|
|
your kernel.
|
|
|
|
In addition, some Linux distributions may have bugs in their versions
|
|
of the kernel that cause packets not to be given high-resolution time
|
|
stamps even if the TSC is enabled. See, for example, bug 61111 for Red
|
|
Hat Linux 7.2. If your distribution has a bug such as this, you may
|
|
have to run a standard kernel from kernel.org in order to get
|
|
high-resolution time stamps.
|
|
|
|
Q 5.9: I'm capturing packets on {Windows 95, Windows 98, Windows Me};
|
|
why are the time stamps on packets wrong?
|
|
|
|
A: This is due to a bug in WinPcap. The bug should be fixed in the
|
|
WinPcap 3.0 alpha release - note that it's an alpha release, so it may
|
|
be buggier than the current production release of WinPcap; please
|
|
report those bugs to the WinPcap developers, and help them try to
|
|
track down the problem, so that they can fix it for the final release.
|
|
|
|
Q 5.10: When I try to run Ethereal on Windows, it fails to run because
|
|
it can't find packet.dll.
|
|
|
|
A: In older versions of Ethereal, there were two binary distributions
|
|
available for Windows, one that supported capturing packets, and one
|
|
that didn't. The version that supported capturing packets required
|
|
that you install the WinPcap driver; if you didn't install it, it
|
|
would fail to run because it couldn't find packet.dll.
|
|
|
|
The current version of Ethereal has only one binary distribution for
|
|
Windows; that version will check whether WinPcap is installed and, if
|
|
it's not, will disable support for packet capture.
|
|
|
|
The WinPcap driver and libraries can be downloaded from the WinPcap
|
|
Web site, the local mirror of the WinPcap Web site, or the
|
|
Wiretapped.net mirror of the WinPcap site.
|
|
|
|
Q 5.11: Why does some network interface on my machine not show up in
|
|
the list of interfaces in the "Interface:" field in the dialog box
|
|
popped up by "Capture->Start", and/or why does Ethereal give me an
|
|
error if I try to capture on that interface?
|
|
|
|
A: If you are running Ethereal on a UNIX-flavored platform, you may
|
|
need to run Ethereal from an account with sufficient privileges to
|
|
capture packets, such as the super-user account. Only those interfaces
|
|
that Ethereal can open for capturing show up in that list; if you
|
|
don't have sufficient privileges to capture on any interfaces, no
|
|
interfaces will show up in the list.
|
|
|
|
If you are running Ethereal on Windows NT 4.0, Windows 2000, Windows
|
|
XP, or Windows Server, and this is the first time you have run a
|
|
WinPcap-based program (such as Ethereal, or Tethereal, or WinDump, or
|
|
Analyzer, or...) since the machine was rebooted, you need to run that
|
|
program from an account with administrator privileges; once you have
|
|
run such a program, you will not need administrator privileges to run
|
|
any such programs until you reboot.
|
|
|
|
If you are running on a UNIX-flavored platform and have sufficient
|
|
privileges, or if you are running on Windows 95/98/Me, or if you are
|
|
running on Windows NT 4.0/2000/XP/Server and have administrator
|
|
privileges or a WinPcap program has been run with those privileges
|
|
since the machine rebooted, then note that Ethereal relies on the
|
|
libpcap library, and on the facilities that come with the OS on which
|
|
it's running in order to do captures; on Windows, it also relies on
|
|
the device driver that comes with WinPcap (which is a version of
|
|
libpcap for Windows).
|
|
|
|
Therefore, if the OS, the libpcap library, or the WinPcap driver don't
|
|
support capturing on a particular network interface device, Ethereal
|
|
won't be able to capture on that device.
|
|
|
|
On Linux, note that you need to have "packet socket" support enabled
|
|
in your kernel; see the "Packet socket" item in the Linux
|
|
"Configure.help" file.
|
|
|
|
On BSD, note that you need to have BPF support enabled in your kernel;
|
|
see the documentation for your system for information on how to enable
|
|
BPF support (if it's not enabled by default on your system).
|
|
|
|
On DEC OSF/1, Digital UNIX, or Tru64 UNIX, note that you need to have
|
|
packet filtering support in your kernel; the doconfig command will
|
|
allow you to configure and build a new kernel with that option.
|
|
|
|
On Windows, note that:
|
|
* 2.02 and earlier versions of the WinPcap driver and library that
|
|
Ethereal uses for packet capture didn't support Token Ring
|
|
interfaces; the current version, 2.3, does support Token Ring, and
|
|
the current version of Ethereal works with (and, in fact,
|
|
requires) WinPcap 2.1 or later.
|
|
If you are having problems capturing on Token Ring interfaces, and
|
|
you have WinPcap 2.02 or an earlier version of WinPcap installed,
|
|
you should uninstall WinPcap, download and install the current
|
|
version of WinPcap, and then install the latest version of
|
|
Ethereal.
|
|
* On Windows 95, 98, or Me, sometimes more than one interface will
|
|
be given the same name; if that is the case, you will only be able
|
|
to capture on one of those interfaces - it's not clear to which
|
|
one the name, when used in a WinPcap application, will refer. For
|
|
example, if you have a PPP serial interface and a VPN interface,
|
|
they might show up with the same name, for example "ppp-mac", and
|
|
if you try to capture on "ppp-mac", it might not capture on the
|
|
interface you're currently using. In that case, you might, for
|
|
example, have to remove the VPN interface from the system in order
|
|
to capture on the PPP serial interface.
|
|
* WinPcap doesn't support PPP WAN interfaces on Windows
|
|
NT/2000/XP/Server, so Ethereal cannot capture packets on those
|
|
devices when running on Windows NT/2000/XP/Server. Regular dial-up
|
|
lines, ISDN lines, and various other lines such as T1/E1 lines are
|
|
all PPP interfaces. This may cause the interface not to show up on
|
|
the list of interfaces in the "Capture Options" dialog.
|
|
* WinPcap currently does not support multiprocessor machines (note
|
|
that machines with a single multi-threaded processor, such as
|
|
Intel's new multi-threaded x86 processors, are multiprocessor
|
|
machines as far as the OS and WinPcap are concerned), and recent
|
|
versions refuse to operate if they detect that they're running on
|
|
a multiprocessor machine, which means that they may not show any
|
|
network interfaces.
|
|
|
|
If you are having trouble capturing on a particular network interface,
|
|
and you've made sure that (on platforms that require it) you've
|
|
arranged that packet capture support is present, as per the above,
|
|
first try capturing on that device with tcpdump - or, on Windows, the
|
|
tcpdump port to Windows, named WinDump; see the WinDump Web site, the
|
|
local mirror of the WinDump Web site, or the Wiretapped.net mirror of
|
|
the WinDump site, for information on using WinDump.
|
|
|
|
If you can capture on the interface with tcpdump/WinDump, send mail to
|
|
ethereal-users@ethereal.com giving full details of the problem,
|
|
including
|
|
* the operating system you're using, and the version of that
|
|
operating system (for Linux, give both the version number of the
|
|
kernel and the name and version number of the distribution you're
|
|
using);
|
|
* the type of network device you're using;
|
|
* the error message you get from Ethereal.
|
|
|
|
If you cannot capture on the interface with tcpdump/WinDump, this is
|
|
almost certainly a problem with one or more of:
|
|
* the operating system you're using;
|
|
* the device driver for the interface you're using;
|
|
* the libpcap/WinPcap library and, if this is Windows, the WinPcap
|
|
device driver;
|
|
|
|
so:
|
|
* if you are using Windows, first check the WinPcap FAQ, the local
|
|
mirror of that FAQ, or the Wiretapped.net mirror of that FAQ, to
|
|
see if your problem is mentioned there. If not, then see the
|
|
WinPcap support page (or the local mirror of that page) - check
|
|
the "Submitting bugs" section;
|
|
* if you are using some Linux distribution, some version of BSD, or
|
|
some other UNIX-flavored OS, you should report the problem to the
|
|
company or organization that produces the OS (in the case of a
|
|
Linux distribution, report the problem to whoever produces the
|
|
distribution).
|
|
|
|
You may also want to ask the ethereal-users@ethereal.com and, if this
|
|
is a UNIX-flavored platform, tcpdump-workers@tcpdump.org mailing lists
|
|
to see if anybody happens to know about the problem and know a
|
|
workaround or fix for the problem. In your mail, please give full
|
|
details of the problem, as described above, and also indicate that the
|
|
problem occurs with tcpdump/WinDump, not just with Ethereal.
|
|
|
|
Q 5.12: I'm running Ethereal on Windows NT/2000/XP/Server; my machine
|
|
has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
|
|
"Interface" item in the "Capture Options" dialog box. Why can no
|
|
packets be sent on or received from that network while I'm trying to
|
|
capture traffic on that interface?
|
|
|
|
A: WinPcap doesn't support PPP WAN interfaces on Windows
|
|
NT/2000/XP/Server; one symptom that may be seen is that attempts to
|
|
capture in promiscuous mode on the interface cause the interface to be
|
|
incapable of sending or receiving packets. You can disable promiscuous
|
|
mode using the -p command-line flag or the item in the "Capture
|
|
Preferences" dialog box, but this may mean that outgoing packets, or
|
|
incoming packets, won't be seen in the capture.
|
|
|
|
Q 5.13: I'm running Ethereal on Windows 95/98/Me, on a machine with
|
|
more than one network adapter of the same type; Ethereal shows all of
|
|
those adapters with the same name, but I can't use any of those
|
|
adapters other than the first one.
|
|
|
|
A: Unfortunately, Windows 95/98/Me gives the same name to multiple
|
|
instances of the type of same network adapter. Therefore, WinPcap
|
|
cannot distinguish between them, so a WinPcap-based application can
|
|
capture only on the first such interface; Ethereal is a
|
|
libpcap/WinPcap-based application.
|
|
|
|
Q 5.14: I have an XXX network card on my machine; if I try to capture
|
|
on it, my machine crashes or resets itself.
|
|
|
|
A: This is almost certainly a problem with one or more of:
|
|
* the operating system you're using;
|
|
* the device driver for the interface you're using;
|
|
* the libpcap/WinPcap library and, if this is Windows, the WinPcap
|
|
device driver;
|
|
|
|
so:
|
|
* if you are using Windows, see the WinPcap support page (or the
|
|
local mirror of that page) - check the "Submitting bugs" section;
|
|
* if you are using some Linux distribution, some version of BSD, or
|
|
some other UNIX-flavored OS, you should report the problem to the
|
|
company or organization that produces the OS (in the case of a
|
|
Linux distribution, report the problem to whoever produces the
|
|
distribution).
|
|
|
|
Q 5.15: My machine crashes or resets itself when I select "Start" from
|
|
the "Capture" menu or select "Preferences" from the "Edit" menu.
|
|
|
|
A: Both of those operations cause Ethereal to try to build a list of
|
|
the interfaces that it can open; it does so by getting a list of
|
|
interfaces and trying to open them. There is probably an OS, driver,
|
|
or, for Windows, WinPcap bug that causes the system to crash when this
|
|
happens; see the previous question.
|
|
|
|
Q 5.16: Does Ethereal work on Windows ME?
|
|
|
|
A: Yes, but if you want to capture packets, you will need to install
|
|
the latest version of WinPcap, as 2.02 and earlier versions of WinPcap
|
|
didn't support Windows ME. You should also install the latest version
|
|
of Ethereal as well.
|
|
|
|
Q 5.17: Does Ethereal work on Windows XP?
|
|
|
|
A: Yes, but if you want to capture packets, you will need to install
|
|
the latest version of WinPcap, as 2.2 and earlier versions of WinPcap
|
|
didn't support Windows XP.
|
|
|
|
Q 5.18: Why doesn't Ethereal correctly identify RTP packets? It shows
|
|
them only as UDP.
|
|
|
|
A: Ethereal can identify a UDP datagram as containing a packet of a
|
|
particular protocol running atop UDP only if
|
|
1. The protocol in question has a particular standard port number,
|
|
and the UDP source or destination port number is that port
|
|
2. Packets of that protocol can be identified by looking for a
|
|
"signature" of some type in the packet - i.e., some data that, if
|
|
Ethereal finds it in some particular part of a packet, means that
|
|
the packet is almost certainly a packet of that type.
|
|
3. Some other traffic earlier in the capture indicated that, for
|
|
example, UDP traffic between two particular addresses and ports
|
|
will be RTP traffic.
|
|
|
|
RTP doesn't have a standard port number, so 1) doesn't work; it
|
|
doesn't, as far as I know, have any "signature", so 2) doesn't work.
|
|
|
|
That leaves 3). If there's RTSP traffic that sets up an RTP session,
|
|
then, at least in some cases, the RTSP dissector will set things up so
|
|
that subsequent RTP traffic will be identified. Currently, that's the
|
|
only place we do that; there may be other places.
|
|
|
|
However, there will always be places where Ethereal is simply
|
|
incapable of deducing that a given UDP flow is RTP; a mechanism would
|
|
be needed to allow the user to specify that a given conversation
|
|
should be treated as RTP. As of Ethereal 0.8.16, such a mechanism
|
|
exists; if you select a UDP or TCP packet, the right mouse button menu
|
|
will have a "Decode As..." menu item, which will pop up a dialog box
|
|
letting you specify that the source port, the destination port, or
|
|
both the source and destination ports of the packet should be
|
|
dissected as some particular protocol.
|
|
|
|
Q 5.19: Why doesn't Ethereal show Yahoo Messenger packets in captures
|
|
that contain Yahoo Messenger traffic?
|
|
|
|
A: Ethereal only recognizes as Yahoo Messenger traffic packets to or
|
|
from TCP port 3050 that begin with "YPNS" or "YHOO". This means that
|
|
1. TCP segments that start with the middle of a Yahoo Messenger
|
|
packet that takes more than one TCP segment will not be recognized
|
|
as Yahoo Messenger packets (even if the TCP segment also contains
|
|
the beginning of another Yahoo Messenger packet);
|
|
2. Yahoo Messenger packets that begin with "YMSG", as packets for
|
|
some versions of the protocol apparently do, will not be
|
|
recognized as Yahoo Messenger packets.
|
|
|
|
Q 5.20: Why do I get the error
|
|
|
|
Gdk-ERROR **: Palettized display (256-colour) mode not supported on
|
|
Windows.
|
|
aborting....
|
|
|
|
when I try to run Ethereal on Windows?
|
|
|
|
A: Ethereal is built using the GTK+ toolkit, which supports most
|
|
UNIX-flavored OSes, and also supports Windows; that toolkit doesn't
|
|
support 256-color mode on Windows - it requires HiColor (16-bit
|
|
colors) or more. If your display supports more than 256 colors, switch
|
|
to a display mode with more colors; if it doesn't support more than
|
|
256 colors, you will be unable to run Ethereal.
|
|
|
|
Q 5.21: When I capture on Windows in promiscuous mode, I can see
|
|
packets other than those sent to or from my machine; however, those
|
|
packets show up with a "Short Frame" indication, unlike packets to or
|
|
from my machine. What should I do to arrange that I see those packets
|
|
in their entirety?
|
|
|
|
A: In at least some cases, this appears to be the result of PGPnet
|
|
running on the network interface on which you're capturing; turn it
|
|
off on that interface.
|
|
|
|
Q 5.22: How can I capture raw 802.11 packets, including non-data
|
|
(management, beacon) packets?
|
|
|
|
A: The answer to this depends on the operating system on which you're
|
|
running and the 802.11 interface you're using.
|
|
|
|
Cisco Aironet cards:
|
|
|
|
The only platforms that allow Ethereal to capture raw 802.11 packets
|
|
on Cisco Aironet cards are:
|
|
* Linux, with a 2.4.6 or later kernel;
|
|
* FreeBSD 4.6 or later, as the driver in FreeBSD 4.5 has bugs that
|
|
cause packets not to be captured correctly, and the driver in
|
|
releases prior to 4.5 didn't support capturing raw packets.
|
|
|
|
On FreeBSD, the ancontrol utility must be used; do not enable the full
|
|
Aironet header via BPF, as Ethereal doesn't currently support that.
|
|
|
|
On Linux, you will need to do
|
|
|
|
echo "Mode: rfmon" >/proc/driver/aironet/ethN/Config
|
|
|
|
if your Aironet card is ethN. To capture traffic from any BSS, do
|
|
|
|
echo "Mode: y" >/proc/driver/aironet/ethN/Config
|
|
|
|
and to return to the normal mode, do
|
|
|
|
echo "Mode: ess" >/proc/driver/aironet/ethN/Config
|
|
|
|
In either case, Ethereal would have to be linked with libpcap 0.7.1 or
|
|
later; this means that most Ethereal binary packages won't work unless
|
|
they're statically linked with libpcap 0.7.1 or later, or they're
|
|
dynamically linked with libpcap and your system has a libpcap 0.7.1 or
|
|
later shared library installed (note that libpcap source package from
|
|
tcpdump.org does not build shared libraries).
|
|
|
|
Cards using the Prism II chip set (see this page of Linux 802.11
|
|
information for details on wireless cards, including information on
|
|
the chips they use):
|
|
|
|
You can capture raw 802.11 packets with Prism II cards on Linux
|
|
systems with the 0.1.14-pre1 or later version of the linux-wlan-ng
|
|
drivers (see the linux-wlan page, and the linux-wlan-ng tarball
|
|
directory), or with Solomon Peachy's patches to the linux-wlan-ng
|
|
0.1.13 drivers (see the `0132-packet-v71.diff' link on his software
|
|
page; the patch speaks of 0.1.13-pre2, but appears to apply to 0.1.13
|
|
as well). If you are using the 0.1.13 drivers, you might also want his
|
|
`0132-promisc-v23.diff' patch as well; if you are using the
|
|
0.1.14-pre1 drivers, you might also want his
|
|
`014p1-promiscfixes-v1.diff' patches - both of those are already in
|
|
0.1.14-pre2.
|
|
|
|
Those require either Solomon's patch to libpcap 0.7.1 (see his
|
|
`libpcap-0.7.1-prism.diff' file, or his RPMs of that version of
|
|
libpcap), or the current CVS version of libpcap, which includes his
|
|
patch (download it from the `Current Tar files' section of the
|
|
tcpdump.org Web site).
|
|
|
|
You may have to run a command to put the interface into monitor mode,
|
|
or to change other interface settings.
|
|
Earlier versions of the linux-wlan-ng drivers don't allow Ethereal to
|
|
directly capture raw 802.11 packets on Prism II cards; however, on
|
|
Linux systems with the linux-wlan-ng drivers version 0.1.6, the
|
|
Prismdump utility can be used to capture packets; it saves packets in
|
|
a form that Ethereal can read. Prismdump can be downloaded from this
|
|
page on the developer.axis.com Web site.
|
|
|
|
On other platforms, capturing raw 802.11 packets on Prism II cards is
|
|
not currently supported.
|
|
|
|
Orinoco Silver and Gold cards:
|
|
|
|
On Linux systems, when using either the orinoco_cs-0.09b driver or the
|
|
driver in at least some versions of the Linux kernel, the
|
|
`orinoco-09b-packet-1.diff' patch on the Orinoco Monitor Mode Patch
|
|
Page should allow you to do capture raw 802.11 packets.
|
|
|
|
The patch appears to apply to the driver in the 2.4.18 kernel, but we
|
|
don't know whether it works; the directions on that page are for the
|
|
pcmcia-cs drivers, not for the driver in the kernel itself.
|
|
Note that the page indicates that not all versions of the Orinoco
|
|
firmware support this patch. The Orinoco patches require Solomon
|
|
Peachy's libpcap patches.
|
|
|
|
On other platforms, capturing raw 802.11 packets on Orinoco cards is
|
|
not currently supported.
|
|
|
|
Other 802.11 interfaces:
|
|
|
|
With other 802.11 interfaces, no platform allows Ethereal to capture
|
|
raw 802.11 packets, as far as we know. If you know of other 802.11
|
|
interfaces that are supported (note that there are many `Prism II
|
|
cards', so your card might be a Prism II card), please let us know,
|
|
and include URLs for sites containing any necessary patches to add
|
|
this support.
|
|
|
|
On platforms that don't allow Ethereal to capture raw 802.11 packets,
|
|
the 802.11 network will appear like an Ethernet to Ethereal.
|
|
|
|
Q 5.23: How can I capture packets with CRC errors?
|
|
|
|
A: Ethereal can capture only the packets that the packet capture
|
|
library - libpcap on UNIX-flavored OSes, and the WinPcap port to
|
|
Windows of libpcap on Windows - can capture, and libpcap/WinPcap can
|
|
capture only the packets that the OS's raw packet capture mechanism
|
|
(or the WinPcap driver, and the underlying OS networking code and
|
|
network interface drivers, on Windows) will allow it to capture.
|
|
|
|
Unless the OS can be configured to supply packets with errors such as
|
|
invalid CRCs to the raw packet capture mechanism, Ethereal - and other
|
|
programs that capture raw packets, such as tcpdump - cannot capture
|
|
those packets. You will have to determine whether your OS can be so
|
|
configured, configure it if possible, and make whatever changes to
|
|
libpcap and the packet capture program you're using are necessary to
|
|
support capturing those packets.
|
|
|
|
Q 5.24: How can I capture entire frames, including the FCS?
|
|
|
|
A: Ethereal can't capture any data that the packet capture library -
|
|
libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of
|
|
libpcap on Windows - can capture, and libpcap/WinPcap can capture only
|
|
the data that the OS's raw packet capture mechanism (or the WinPcap
|
|
driver, and the underlying OS networking code and network interface
|
|
drivers, on Windows) will allow it to capture.
|
|
|
|
For any particular link-layer network type, unless the OS supplies the
|
|
FCS of a frame as part of the frame, or can be configured to supply
|
|
the FCS of a frame as part of the frame, Ethereal - and other programs
|
|
that capture raw packets, such as tcpdump - cannot capture the FCS of
|
|
a frame. You will have to determine whether your OS can be so
|
|
configured, configure it if possible, and make whatever changes to
|
|
libpcap and the packet capture program you're using are necessary to
|
|
support capturing the FCS of a frame. Most if not all OSes probably do
|
|
not support capturing the FCS of a frame on Ethernet, and probably do
|
|
not support it on most other link-layer types.
|
|
|
|
Q 5.25: Ethereal hangs after I stop a capture.
|
|
|
|
A: The most likely reason for this is that Ethereal is trying to look
|
|
up an IP address in the capture to convert it to a name (so that, for
|
|
example, it can display the name in the source address or destination
|
|
address columns), and that lookup process is taking a very long time.
|
|
|
|
Ethereal calls a routine in the OS of the machine on which it's
|
|
running to convert of IP addresses to the corresponding names. That
|
|
routine probably does one or more of:
|
|
* a search of a system file listing IP addresses and names;
|
|
* a lookup using DNS;
|
|
* on UNIX systems, a lookup using NIS;
|
|
* on Windows systems, a NetBIOS-over-TCP query.
|
|
|
|
If a DNS server that's used in an address lookup is not responding,
|
|
the lookup will fail, but will only fail after a timeout while the
|
|
system routine waits for a reply.
|
|
|
|
In addition, on Windows systems, if the DNS lookup of the address
|
|
fails, either because the server isn't responding or because there are
|
|
no records in the DNS that could be used to map the address to a name,
|
|
a NetBIOS-over-TCP query will be made. That query involves sending a
|
|
message to the NetBIOS-over-TCP name service on that machine, asking
|
|
for the name and other information about the machine. If the machine
|
|
isn't running software that responds to those queries - for example,
|
|
many non-Windows machines wouldn't be running that software - the
|
|
lookup will only fail after a timeout. Those timeouts can cause the
|
|
lookup to take a long time.
|
|
|
|
If you disable network address-to-name translation - for example, by
|
|
turning off the `Enable network name resolution' option in the `Name
|
|
resolution' options in the dialog box you get by selecting
|
|
`Preferences' from the `Edit' menu - the lookups of the address won't
|
|
be done, which may speed up the process of reading the capture file
|
|
after the capture is stopped. You can make that setting the default by
|
|
using the `Save' button in that dialog box; note that this will save
|
|
all your current preference settings.
|
|
|
|
If Ethereal hangs when reading a capture even with network name
|
|
resolution turned off, there might, for example, be a bug in one of
|
|
Ethereal's dissectors for a protocol causing it to loop infinitely.
|
|
The bug should be reported to the Ethereal developers' mailing list at
|
|
ethereal-dev@ethereal.com.
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On UNIX-flavored OSes, please try to force Ethereal to dump core, by
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sending it a SIGABRT signal (usually signal 6) with the kill command,
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and then get a stack trace if you have a debugger installed. A stack
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trace can be obtained by using your debugger (gdb in this example),
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the Ethereal binary, and the resulting core file. Here's an example of
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how to use the gdb command backtrace to do so.
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$ gdb ethereal core
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(gdb) backtrace
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..... prints the stack trace
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(gdb) quit
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$
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The core dump file may be named "ethereal.core" rather than "core" on
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some platforms (e.g., BSD systems)
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Also, if at all possible, please send a copy of the capture file that
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caused the problem; when capturing packets, Ethereal normally writes
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captured packets to a temporary file, which will probably be in /tmp
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or /var/tmp on UNIX-flavored OSes and \TEMP on Windows, so the capture
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file will probably be there. It will have a name beginning with ether,
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with some mixture of letters and numbers after that. Please don't send
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a trace file greater than 1 MB when compressed. If the trace file
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contains sensitive information (e.g., passwords), then please do not
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send it.
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Q 5.26: How can I search for, or filter, packets that have a
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particular string anywhere in them?
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A: Currently, you can't.
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That's a feature that would be hard to implement in capture filters
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without changes to the capture filter code, which, on many platforms,
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is in the OS kernel and, on other platforms, is in the libpcap
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library.
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It would be easier to implement in display filters, but it hasn't been
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implemented yet. It would be best implemented as a display filter
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"string match" operator, which would let you check not only the entire
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packet for a string, but check portions of the packet for a string. It
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should probably not use a naive string matching mechanism, as there
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are mechanisms much faster than the naive one.
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Support can be found on the ethereal-users[AT]ethereal.com mailing
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list.
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For corrections/additions/suggestions for this page, please send email
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to: ethereal-web[AT]ethereal.com
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Last modified: Sun, February 09 2003.
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