1286 lines
56 KiB
Text
1286 lines
56 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 the 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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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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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've just installed Ethereal, and the traffic on my local LAN is
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boring.
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5.6 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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5.7 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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5.8 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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5.9 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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5.10 I'm running Ethereal on Windows; why doesn't my my (Token Ring,
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PPP) network interface show up in the list of interfaces in the
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"Interface" item in the "Capture Preferences" dialog box popped up by
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the "Capture->Start" menu item?
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5.11 I'm running Ethereal on Windows NT/2000/XP/.NET Server; my
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machine has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows
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up in the "Interface" item in the "Capture Preferences" dialog box.
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Why can no packets be sent on or received from that network while I'm
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trying to capture traffic on that interface?
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5.12 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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5.13 I have an XXX network card on my machine; it doesn't show up in
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the list of interfaces in the "Interface:" field in the dialog box
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popped up by "Capture->Start", and/or Ethereal gives me an error if I
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try to capture on that interface.
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5.14 There are no interfaces in the drop-down list of interfaces in
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the "Interface:" field in the dialog box popped up by
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"Capture->Start".
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5.15 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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5.16 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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5.17 Does Ethereal work on Windows ME?
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5.18 Does Ethereal work on Windows XP?
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5.19 Why doesn't Ethereal correctly identify RTP packets? It shows
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them only as UDP.
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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 I'm capturing packets on {Windows 95, Windows 98, Windows Me};
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why are the time stamps on packets wrong?
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5.22 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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5.23 How can I capture raw 802.11 packets, including non-data
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(management, beacon) packets?
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5.24 How can I capture packets with CRC errors?
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5.25 How can I capture entire frames, including the FCS?
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5.26 Ethereal hangs after I stop a capture.
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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 280 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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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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Async data over ISDN (V.120)
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ATM
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ATM LAN Emulation
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Authentication 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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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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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 SLARP
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Common Open Policy Service
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Common Unix Printing System (CUPS) Browsing Protocol
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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 RPC
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DCE/RPC Conversation Manager
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DCE/RPC Endpoint Mapper
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DCE/RPC Remote Management
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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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Domain Name Service
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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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Fiber Distributed Data Interface
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File Transfer Protocol (FTP)
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Frame
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Frame Relay
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FTP Data
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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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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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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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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 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 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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Message Transfer Part Level 2
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Message Transfer Part Level 3
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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 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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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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NSPI
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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 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 Link 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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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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Remote Procedure Call
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Remote Quota
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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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Short Message Peer to Peer
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Signalling Connection Control Part
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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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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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Syslog message
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Systems Network Architecture
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TACACS
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TACACS+
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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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Who
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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 Display Manager Control Protocol
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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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|
Q 1.3: Are there any plans to support {your favorite protocol}?
|
||
|
|
||
|
A: Support for particular protocols is added to Ethereal as a result
|
||
|
of people contributing that support; no formal plans for adding
|
||
|
support for particular protocols in particular future releases exist.
|
||
|
|
||
|
Q 1.4: Can Ethereal read capture files from {your favorite network
|
||
|
analyzer}?
|
||
|
|
||
|
A: Support for particular protocols is added to Ethereal as a result
|
||
|
of people contributing that support; no formal plans for adding
|
||
|
support for particular protocols in particular future releases exist.
|
||
|
|
||
|
If a network analyzer writes out files in a format already supported
|
||
|
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
|
||
|
extensions to that format.
|
||
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|
||
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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
|
||
|
read captures from that network analyzer, we would either have to have
|
||
|
a specification for the file format, or the extensions, sufficient to
|
||
|
give us enough information to read the parts of the file relevant to
|
||
|
Ethereal, or would need at least one capture file in that format AND a
|
||
|
detailed textual analysis of the packets in that capture file (showing
|
||
|
packet time stamps, packet lengths, and the top-level packet header)
|
||
|
in order to reverse-engineer the file format.
|
||
|
|
||
|
Note that there is no guarantee that we will be able to
|
||
|
reverse-engineer a capture file format.
|
||
|
|
||
|
Q 1.5: What devices can Ethereal use to capture packets?
|
||
|
|
||
|
A: Ethereal can read live data from Ethernet, Token-Ring, FDDI, serial
|
||
|
(PPP and SLIP) (if the OS on which it's running allows Ethereal to do
|
||
|
so), 802.11 wireless LAN (if the OS on which it's running allows
|
||
|
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
|
||
|
recent versions of libpcap. It can also read a variety of capture file
|
||
|
formats, including:
|
||
|
* libpcap/tcpdump
|
||
|
* snoop
|
||
|
* Shomiti
|
||
|
* LanAlyzer
|
||
|
* Sniffer (compressed and uncompressed)
|
||
|
* MS Network Monitor
|
||
|
* AIX iptrace
|
||
|
* NetXray
|
||
|
* Sniffer Pro
|
||
|
* RADCOM
|
||
|
* Lucent/Ascend debug output
|
||
|
* Toshiba ISDN router "snoop" output
|
||
|
* HPUX nettl
|
||
|
* ISDN4BSD "i4btrace" utility.
|
||
|
* Cisco Secure IDS
|
||
|
* pppd log files (pppdump format)
|
||
|
|
||
|
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, WS_FTP from Ipswitch, or with 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.
|
||
|
|
||
|
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.)
|
||
|
|
||
|
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.
|
||
|
|
||
|
If your machine is not plugged into a switched network, or it is and
|
||
|
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. 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'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 5.6: 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 5.7: 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 5.8: 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 5.9: 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.
|
||
|
|
||
|
Q 5.10: I'm running Ethereal on Windows; why doesn't my my (Token
|
||
|
Ring, PPP) network interface show up in the list of interfaces in the
|
||
|
"Interface" item in the "Capture Preferences" dialog box popped up by
|
||
|
the "Capture->Start" menu item?
|
||
|
|
||
|
A: 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.
|
||
|
|
||
|
WinPcap doesn't support PPP WAN interfaces on Windows NT/2000/XP/.NET
|
||
|
Server, so Ethereal cannot capture packets on those devices when
|
||
|
running on Windows NT/2000/XP/.NET 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 Preferences" dialog.
|
||
|
|
||
|
For problems seen when installing the WinPcap driver or library, or
|
||
|
seen when capturing, 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.
|
||
|
|
||
|
Q 5.11: I'm running Ethereal on Windows NT/2000/XP/.NET Server; my
|
||
|
machine has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows
|
||
|
up in the "Interface" item in the "Capture Preferences" 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/.NET 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 5.12: 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 5.13: I have an XXX network card on my machine; it doesn't show up
|
||
|
in the list of interfaces in the "Interface:" field in the dialog box
|
||
|
popped up by "Capture->Start", and/or Ethereal gives me an error if I
|
||
|
try to capture on that interface.
|
||
|
|
||
|
A: 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.
|
||
|
|
||
|
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, 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 5.14: There are no interfaces in the drop-down list of interfaces in
|
||
|
the "Interface:" field in the dialog box popped up by
|
||
|
"Capture->Start".
|
||
|
|
||
|
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, or
|
||
|
Windows XP, 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 and have administrator privileges or
|
||
|
a WinPcap program has been run with those privileges since the machine
|
||
|
rebooted, this is the same problem as in the previous question; see
|
||
|
the answer to that question.
|
||
|
|
||
|
Q 5.15: 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 5.16: 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 5.17: 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 5.18: 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 5.19: 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 5.20: 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: 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. A future release of WinPcap will
|
||
|
fix that bug.
|
||
|
|
||
|
Q 5.22: 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 5.23: 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 5.24: 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 5.25: 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 5.26: 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
|
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|
running to convert of IP addresses to the corresponding names. That
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|
routine probably does one or more of:
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|
* a search of a system file listing IP addresses and names;
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|
* a lookup using DNS;
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|
* on UNIX systems, a lookup using NIS;
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|
* on Windows systems, a NetBIOS-over-TCP query.
|
||
|
|
||
|
If a DNS server that's used in an address lookup is not responding,
|
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|
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.
|
||
|
|
||
|
On UNIX-flavored OSes, please try to force Ethereal to dump core, by
|
||
|
sending it a SIGABRT signal (usually signal 6) with the kill command,
|
||
|
and then get a stack trace if you have a debugger installed. A stack
|
||
|
trace can be obtained by using your debugger (gdb in this example),
|
||
|
the Ethereal binary, and the resulting core file. Here's an example of
|
||
|
how to use the gdb command backtrace to do so.
|
||
|
$ gdb ethereal core
|
||
|
(gdb) backtrace
|
||
|
..... prints the stack trace
|
||
|
(gdb) quit
|
||
|
$
|
||
|
|
||
|
The core dump file may be named "ethereal.core" rather than "core" on
|
||
|
some platforms (e.g., BSD systems)
|
||
|
|
||
|
Also, if at all possible, please send a copy of the capture file that
|
||
|
caused the problem; when capturing packets, Ethereal normally writes
|
||
|
captured packets to a temporary file, which will probably be in /tmp
|
||
|
or /var/tmp on UNIX-flavored OSes and \TEMP on Windows, so the capture
|
||
|
file will probably be there. It will have a name beginning with ether,
|
||
|
with some mixture of letters and numbers after that. Please don't send
|
||
|
a trace file greater than 1 MB when compressed. If the trace file
|
||
|
contains sensitive information (e.g., passwords), then please do not
|
||
|
send it.
|
||
|
|
||
|
|
||
|
Support can be found on the ethereal-users[AT]ethereal.com mailing
|
||
|
list.
|
||
|
For corrections/additions/suggestions for this page, please send email
|
||
|
to: ethereal-web[AT]ethereal.com
|
||
|
Last modified: Sun, August 11 2002.
|