forked from osmocom/wireshark
822 lines
34 KiB
Plaintext
822 lines
34 KiB
Plaintext
++++++++++++++++++++++++++++++++++++++
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<!-- WSUG Chapter Work -->
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++++++++++++++++++++++++++++++++++++++
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[[ChapterWork]]
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== Working with captured packets
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[[ChWorkViewPacketsSection]]
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=== Viewing packets you have captured
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Once you have captured some packets or you have opened a previously saved
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capture file, you can view the packets that are displayed in the packet list
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pane by simply clicking on a packet in the packet list pane, which will bring up
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the selected packet in the tree view and byte view panes.
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You can then expand any part of the tree to view detailed information about each
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protocol in each packet. Clicking on an item in the tree will highlight the
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corresponding bytes in the byte view. An example with a TCP packet selected is
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shown in <<ChWorkSelPack1>>. It also has the Acknowledgment number in the TCP
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header selected, which shows up in the byte view as the selected bytes.
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[[ChWorkSelPack1]]
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.Wireshark with a TCP packet selected for viewing
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image::wsug_graphics/ws-packet-selected.png[]
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You can also select and view packets the same way while Wireshark is capturing
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if you selected ``Update list of packets in real time'' in the ``Capture
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Preferences'' dialog box.
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In addition you can view individual packets in a separate window as shown in
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<<ChWorkPacketSepView>>. You can do this by double-clicking on an item in the
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packet list or by selecting the packet in which you are interested in the packet
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list pane and selecting menu:View[Show Packet in New Window]. This allows you to
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easily compare two or more packets, even across multiple files.
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[[ChWorkPacketSepView]]
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.Viewing a packet in a separate window
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image::wsug_graphics/ws-packet-sep-win.png[]
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Along with double-clicking the packet list and using the main menu there are a
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number of other ways to open a new packet window:
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- Hold down the shift key and double-click on a frame link in the packet
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details.
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- From <<PacketListPopupMenuTable>>.
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- From <<PacketDetailsPopupMenuTable>>.
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[[ChWorkDisplayPopUpSection]]
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=== Pop-up menus
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You can bring up a pop-up menu over either the ``Packet List'', its column header,
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or ``Packet Details'' pane by clicking your right mouse button at the
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corresponding pane.
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[[ChWorkColumnHeaderPopUpMenuSection]]
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==== Pop-up menu of the ``Packet List'' column header
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[[ChWorkColumnHeaderPopUpMenu]]
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.Pop-up menu of the ``Packet List'' column header
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image::wsug_graphics/ws-column-header-popup-menu.png[]
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The following table gives an overview of which functions are available in this
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header, where to find the corresponding function in the main menu, and a short
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description of each item.
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[[ColumnHeaderPopupMenuTable]]
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.The menu items of the ``Packet List'' column header pop-up menu
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[options="header"]
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|===============
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|Item|Identical to main menu's item:|Description
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|menu:Sort Ascending[]|| Sort the packet list in ascending order based on this column.
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|menu:Sort Descending[]|| Sort the packet list in descending order based on this column.
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|menu:No Sort[]|| Remove sorting order based on this column.
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|menu:Align Left[]|| Set left alignment of the values in this column.
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|menu:Align Center[]|| Set center alignment of the values in this column.
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|menu:Align Right[]|| Set right alignment of the values in this column.
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|menu:Column Preferences...[]|| Open the Preferences dialog box on the column tab.
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|menu:Resize Column[]|| Resize the column to fit the values.
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|menu:Rename Column Title[]|| Allows you to change the title of the column header.
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|menu:Displayed Column[]|menu:View[]| This menu items folds out with a list of all configured columns. These columns can now be shown or hidden in the packet list.
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|menu:Hide Column[]|| Allows you to hide the column from the packet list.
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|menu:Remove Column[]|| Allows you to remove the column from the packet list.
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|===============
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[[ChWorkPacketListPanePopUpMenuSection]]
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==== Pop-up menu of the ``Packet List'' pane
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[[ChWorkPacketListPanePopUpMenu]]
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.Pop-up menu of the ``Packet List'' pane
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image::wsug_graphics/ws-packet-pane-popup-menu.png[]
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The following table gives an overview of which functions are available in this pane, where to find the corresponding function in the main menu, and a short description of each item.
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[[PacketListPopupMenuTable]]
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.The menu items of the ``Packet List'' pop-up menu
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[options="header"]
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|===============
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|Item|Identical to main menu's item:|Description
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|menu:Mark Packet (toggle)[]|menu:Edit[]| Mark/unmark a packet.
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|menu:Ignore Packet (toggle)[]|menu:Edit[]| Ignore or inspect this packet while dissecting the capture file.
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|menu:Set Time Reference (toggle)[]|menu:Edit[]| Set/reset a time reference.
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|menu:Manually Resolve Address[]|| Allows you to enter a name to resolve for the selected address.
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|menu:Apply as Filter[]|menu:Analyze[]| Prepare and apply a display filter based on the currently selected item.
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|menu:Prepare a Filter[]|menu:Analyze[]| Prepare a display filter based on the currently selected item.
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|menu:Conversation Filter[]|| This menu item applies a display filter with the address information from the selected packet. E.g. the IP menu entry will set a filter to show the traffic between the two IP addresses of the current packet. XXX - add a new section describing this better.
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|menu:Colorize Conversation[]|| This menu item uses a display filter with the address information from the selected packet to build a new colorizing rule.
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|menu:SCTP[]|| Allows you to analyze and prepare a filter for this SCTP association.
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|menu:Follow TCP Stream[]|menu:Analyze[]| Allows you to view all the data on a TCP stream between a pair of nodes.
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|menu:Follow UDP Stream[]|menu:Analyze[]| Allows you to view all the data on a UDP datagram stream between a pair of nodes.
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|menu:Follow SSL Stream[]|menu:Analyze[]| Same as ``Follow TCP Stream'' but for SSL. XXX - add a new section describing this better.
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|menu:Copy/ Summary (Text)[]|| Copy the summary fields as displayed to the clipboard, as tab-separated text.
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|menu:Copy/ Summary (CSV)[]|| Copy the summary fields as displayed to the clipboard, as comma-separated text.
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|menu:Copy/ As Filter[]|| Prepare a display filter based on the currently selected item and copy that filter to the clipboard.
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|menu:Copy/ Bytes (Offset Hex Text)[]|| Copy the packet bytes to the clipboard in hexdump-like format.
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|menu:Copy/ Bytes (Offset Hex)[]|| Copy the packet bytes to the clipboard in hexdump-like format, but without the text portion.
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|menu:Copy/ Bytes (Printable Text Only)[]|| Copy the packet bytes to the clipboard as ASCII text, excluding non-printable characters.
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|menu:Copy/ Bytes (Hex Stream)[]|| Copy the packet bytes to the clipboard as an unpunctuated list of hex digits.
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|menu:Copy/ Bytes (Binary Stream)[]|| Copy the packet bytes to the clipboard as raw binary. The data is stored in the clipboard as MIME-type ``application/octet-stream''.
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|menu:Decode As...[]|menu:Analyze[]| Change or apply a new relation between two dissectors.
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|menu:Print...[]|File| Print packets.
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|menu:Show Packet in New Window[]|menu:View[]| Display the selected packet in a new window.
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|===============
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[[ChWorkPacketDetailsPanePopUpMenuSection]]
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==== Pop-up menu of the ``Packet Details'' pane
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[[ChWorkPacketDetailsPanePopUpMenu]]
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.Pop-up menu of the ``Packet Details'' pane
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image::wsug_graphics/ws-details-pane-popup-menu.png[]
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The following table gives an overview of which functions are available in this
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pane, where to find the corresponding function in the main menu, and a short
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description of each item.
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[[PacketDetailsPopupMenuTable]]
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.The menu items of the ``Packet Details'' pop-up menu
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[options="header"]
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|===============
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|Item|Identical to main menu's item:|Description
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|menu:Expand Subtrees[]|menu:View[]| Expand the currently selected subtree.
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|menu:Collapse Subtrees[]|menu:View[]| Collapse the currently selected subtree.
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|menu:Expand All[]|menu:View[]| Expand all subtrees in all packets in the capture.
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|menu:Collapse All[]|menu:View[]| Wireshark keeps a list of all the protocol subtrees that are expanded, and uses it to ensure that the correct subtrees are expanded when you display a packet. This menu item collapses the tree view of all packets in the capture list.
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|menu:Apply as Column[]|| Use the selected protocol item to create a new column in the packet list.
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|menu:Apply as Filter[]|menu:Analyze[]| Prepare and apply a display filter based on the currently selected item.
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|menu:Prepare a Filter[]|menu:Analyze[]| Prepare a display filter based on the currently selected item.
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|menu:Colorize with Filter[]|| This menu item uses a display filter with the information from the selected protocol item to build a new colorizing rule.
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|menu:Follow TCP Stream[]|menu:Analyze[]| Allows you to view all the data on a TCP stream between a pair of nodes.
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|menu:Follow UDP Stream[]|menu:Analyze[]| Allows you to view all the data on a UDP datagram stream between a pair of nodes.
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|menu:Follow SSL Stream[]|menu:Analyze[]| Same as ``Follow TCP Stream'' but for SSL. XXX - add a new section describing this better.
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|menu:Copy/ Description[]|menu:Edit[]| Copy the displayed text of the selected field to the system clipboard.
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|menu:Copy/ Fieldname[]|menu:Edit[]| Copy the name of the selected field to the system clipboard.
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|menu:Copy/ Value[]|menu:Edit[]| Copy the value of the selected field to the system clipboard.
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|menu:Copy/ As Filter[]|menu:Edit[]| Prepare a display filter based on the currently selected item and copy it to the clipboard.
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|menu:Copy/ Bytes (Offset Hex Text)[]|| Copy the packet bytes to the clipboard in hexdump-like format; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).
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|menu:Copy/ Bytes (Offset Hex)[]|| Copy the packet bytes to the clipboard in hexdump-like format, but without the text portion; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).
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|menu:Copy/ Bytes (Printable Text Only)[]|| Copy the packet bytes to the clipboard as ASCII text, excluding non-printable characters; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).
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|menu:Copy/ Bytes (Hex Stream)[]|| Copy the packet bytes to the clipboard as an unpunctuated list of hex digits; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).
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|menu:Copy/ Bytes (Binary Stream)[]|| Copy the packet bytes to the clipboard as raw binary; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane). The data is stored in the clipboard as MIME-type ``application/octet-stream''.
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|menu:Export Selected Packet Bytes...[]|menu:File[]| This menu item is the same as the File menu item of the same name. It allows you to export raw packet bytes to a binary file.
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|menu:Wiki Protocol Page[]|| Show the wiki page corresponding to the currently selected protocol in your web browser.
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|menu:Filter Field Reference[]|| Show the filter field reference web page corresponding to the currently selected protocol in your web browser.
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|menu:Protocol Preferences...[]|| The menu item takes you to the properties dialog and selects the page corresponding to the protocol if there are properties associated with the highlighted field. More information on preferences can be found in <<ChCustGUIPrefPage>>.
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|menu:Decode As...[]|menu:Analyze[]| Change or apply a new relation between two dissectors.
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|menu:Disable Protocol[]|| Allows you to temporarily disable a protocol dissector, which may be blocking the legitimate dissector.
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|menu:Resolve Name[]|menu:View[]| Causes a name resolution to be performed for the selected packet, but NOT every packet in the capture.
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|menu:Go to Corresponding Packet[]|menu:Go[]| If the selected field has a corresponding packet, go to it. Corresponding packets will usually be a request/response packet pair or such.
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|===============
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[[ChWorkDisplayFilterSection]]
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=== Filtering packets while viewing
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Wireshark has two filtering languages: One used when capturing packets, and one
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used when displaying packets. In this section we explore that second type of
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filter: Display filters. The first one has already been dealt with in
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<<ChCapCaptureFilterSection>>.
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Display filters allow you to concentrate on the packets you are interested in
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while hiding the currently uninteresting ones. They allow you to select packets
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by:
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* Protocol
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* The presence of a field
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* The values of fields
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* A comparison between fields
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* ... and a lot more!
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To select packets based on protocol type, simply type the protocol in which you
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are interested in the _Filter:_ field in the filter toolbar of the Wireshark
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window and press enter to initiate the filter. <<ChWorkTCPFilter>> shows an
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example of what happens when you type _tcp_ in the filter field.
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[NOTE]
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====
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All protocol and field names are entered in lowercase. Also, don't forget to press enter after entering the filter expression.
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====
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[[ChWorkTCPFilter]]
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.Filtering on the TCP protocol
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image::wsug_graphics/ws-display-filter-tcp.png[]
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As you might have noticed, only packets of the TCP protocol are displayed now
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(e.g. packets 1-10 are hidden). The packet numbering will remain as before, so
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the first packet shown is now packet number 11.
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[NOTE]
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====
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When using a display filter, all packets remain in the capture file. The display
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filter only changes the display of the capture file but not its content!
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====
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You can filter on any protocol that Wireshark understands. You can also filter
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on any field that a dissector adds to the tree view, but only if the dissector
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has added an abbreviation for the field. A list of such fields is available in
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Wireshark in the _Add Expression..._ dialog box. You can find more information
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on the _Add Expression..._ dialog box in <<ChWorkFilterAddExpressionSection>>.
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For example, to narrow the packet list pane down to only those packets to or
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from the IP address 192.168.0.1, use `ip.addr==192.168.0.1`.
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[NOTE]
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====
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To remove the filter, click on the button:[Clear] button to the right of the filter field.
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====
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[[ChWorkBuildDisplayFilterSection]]
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=== Building display filter expressions
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Wireshark provides a simple but powerful display filter language that allows you
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to build quite complex filter expressions. You can compare values in packets as
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well as combine expressions into more specific expressions. The following
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sections provide more information on doing this.
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[TIP]
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====
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You will find a lot of Display Filter examples at the _Wireshark Wiki Display
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Filter page_ at
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link:wireshark-wiki-display-filter:[][wireshark-wiki-display-filter:[]].
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====
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==== Display filter fields
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Every field in the packet details pane can be used as a filter string, this will
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result in showing only the packets where this field exists. For example: the
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filter string: _tcp_ will show all packets containing the tcp protocol.
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There is a complete list of all filter fields available through the menu item
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menu:Help[Supported Protocols] in the page ``Display Filter Fields'' of the
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``Supported Protocols'' dialog.
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// XXX - add some more info here and a link to the statusbar info.
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==== Comparing values
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You can build display filters that compare values using a number of different
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comparison operators. They are shown in <<DispCompOps>>.
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[TIP]
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====
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You can use English and C-like terms in the same way, they can even be mixed in a filter string.
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====
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[[DispCompOps]]
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.Display Filter comparison operators
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[options="header"]
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|===============
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|English|C-like|Description and example
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|eq |== |Equal. `ip.src==10.0.0.5`
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|ne |!= |Not equal. `ip.src!=10.0.0.5`
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|gt |> |Greater than. `frame.len > 10`
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|lt |< |Less than. `frame.len < 128`
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|ge |>= |Greater than or equal to. `frame.len ge 0x100`
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|le |\<= |Less than or equal to. `frame.len <= 0x20`
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|===============
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In addition, all protocol fields have a type. <<ChWorkFieldTypes>> provides a list
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of the types and example of how to express them.
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[[ChWorkFieldTypes]]
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.Display Filter Field Types
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[options="header"]
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|===============
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|Type|Example
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|Unsigned integer (8-bit, 16-bit, 24-bit, 32-bit) |
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You can express integers in decimal, octal, or hexadecimal. The following display filters are equivalent:
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----
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ip.len le 1500
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ip.len le 02734
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ip.len le 0x436
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----
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|Signed integer (8-bit, 16-bit, 24-bit, 32-bit) |
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|Boolean|
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A boolean field is present in the protocol decode only if its value is true. For
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example, _tcp.flags.syn_ is present, and thus true, only if the SYN flag is
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present in a TCP segment header.
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Thus the filter expression _tcp.flags.syn_ will select only those packets for which this flag exists, that is, TCP segments where the segment header contains the SYN flag. Similarly, to find source-routed token ring packets, use a filter expression of _tr.sr_.
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|Ethernet address (6 bytes)|Separators can be a colon (:), dot (.) or dash (-) and can have one or two bytes between separators:
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----
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eth.dst == ff:ff:ff:ff:ff:ff
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eth.dst == ff-ff-ff-ff-ff-ff
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eth.dst == ffff.ffff.ffff
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----
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|IPv4 address|ip.addr == 192.168.0.1
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Classless InterDomain Routing (CIDR) notation can be used to test if an IPv4 address is in a certain subnet. For example, this display filter will find all packets in the 129.111 Class-B network:
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ip.addr == 129.111.0.0/16
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|IPv6 address|ipv6.addr == ::1
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|String (text)|http.request.uri == "https://www.wireshark.org/"
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|===============
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==== Combining expressions
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You can combine filter expressions in Wireshark using the logical operators shown in <<FiltLogOps>>
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[[FiltLogOps]]
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.Display Filter Logical Operations
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[options="header"]
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|===============
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|English|C-like|Description and example
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|and |&&| Logical AND. `ip.src==10.0.0.5 and tcp.flags.fin`
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|or |\|\| | Logical OR. `ip.scr==10.0.0.5 or ip.src==192.1.1.1`
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|xor |^^ | Logical XOR. `tr.dst[0:3] == 0.6.29 xor tr.src[0:3] == 0.6.29`
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|not |! | Logical NOT. `not llc`
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|[...] | |
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Substring Operator.
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Wireshark allows you to select subsequences of a sequence in rather elaborate
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ways. After a label you can place a pair of brackets [] containing a comma
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separated list of range specifiers.
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----
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eth.src[0:3] == 00:00:83
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----
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The example above uses the n:m format to specify a single range. In this case n
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is the beginning offset and m is the length of the range being specified.
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----
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eth.src[1-2] == 00:83
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----
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The example above uses the n-m format to specify a single range. In this case n
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is the beginning offset and m is the ending offset.
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----
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eth.src[:4] == 00:00:83:00
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----
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The example above uses the :m format, which takes everything from the beginning
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of a sequence to offset m. It is equivalent to 0:m
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----
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eth.src[4:] == 20:20
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----
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The example above uses the n: format, which takes everything from offset n to
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the end of the sequence.
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----
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eth.src[2] == 83
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----
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The example above uses the n format to specify a single range. In this case the
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element in the sequence at offset n is selected. This is equivalent to n:1.
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----
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eth.src[0:3,1-2,:4,4:,2] ==
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00:00:83:00:83:00:00:83:00:20:20:83
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----
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Wireshark allows you to string together single ranges in a comma separated list
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to form compound ranges as shown above.
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|===============
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==== Membership Operator.
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Wireshark allows you to test a field for membership in a set of values or
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fields. After the field name, use the in operator followed by the set items
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surrounded by braces {}.
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----
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tcp.port in {80 443 8080}
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----
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This can be considered a shortcut operator, as the previous expression could
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have been expressed as:
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----
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tcp.port == 80 || tcp.port == 443 || tcp.port == 8080
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----
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[[ChWorkBuildDisplayFilterMistake]]
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==== A common mistake
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Using the != operator on combined expressions like eth.addr, ip.addr, tcp.port,
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and udp.port will probably not work as expected.
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Often people use a filter string to display something like `ip.addr == 1.2.3.4`
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which will display all packets containing the IP address 1.2.3.4.
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Then they use `ip.addr != 1.2.3.4` to see all packets not containing the IP
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address 1.2.3.4 in it. Unfortunately, this does _not_ do the expected.
|
|
|
|
Instead, that expression will even be true for packets where either source or
|
|
destination IP address equals 1.2.3.4. The reason for this, is that the
|
|
expression `ip.addr != 1.2.3.4` must be read as ``the packet contains a field
|
|
named ip.addr with a value different from 1.2.3.4''. As an IP datagram contains
|
|
both a source and a destination address, the expression will evaluate to true
|
|
whenever at least one of the two addresses differs from 1.2.3.4.
|
|
|
|
If you want to filter out all packets containing IP datagrams to or from IP
|
|
address 1.2.3.4, then the correct filter is `!(ip.addr == 1.2.3.4)` as it reads
|
|
``show me all the packets for which it is not true that a field named ip.addr
|
|
exists with a value of 1.2.3.4'', or in other words, ``filter out all packets
|
|
for which there are no occurrences of a field named ip.addr with the value
|
|
1.2.3.4''.
|
|
|
|
[[ChWorkFilterAddExpressionSection]]
|
|
|
|
|
|
=== The ``Filter Expression'' dialog box
|
|
|
|
When you are accustomed to Wireshark's filtering system and know what labels you
|
|
wish to use in your filters it can be very quick to simply type a filter string.
|
|
However if you are new to Wireshark or are working with a slightly unfamiliar
|
|
protocol it can be very confusing to try to figure out what to type. The
|
|
``Filter Expression'' dialog box helps with this.
|
|
|
|
[TIP]
|
|
====
|
|
The ``Filter Expression'' dialog box is an excellent way to learn how to write
|
|
Wireshark display filter strings.
|
|
====
|
|
|
|
|
|
[[ChWorkFilterAddExpression1]]
|
|
|
|
.The ``Filter Expression'' dialog box
|
|
image::wsug_graphics/ws-filter-add-expression.png[]
|
|
|
|
When you first bring up the Filter Expression dialog box you are shown a tree
|
|
of field names, organized by protocol, and a box for selecting a relation.
|
|
|
|
_Field Name_::
|
|
Select a protocol field from the protocol field tree. Every protocol with
|
|
filterable fields is listed at the top level. (You can search for a particular
|
|
protocol entry by entering the first few letters of the protocol name). By
|
|
expanding a protocol name you can get a list of the field names available for
|
|
filtering for that protocol.
|
|
|
|
_Relation_::
|
|
Select a relation from the list of available relation. The _is present_ is a
|
|
unary relation which is true if the selected field is present in a packet. All
|
|
other listed relations are binary relations which require additional data (e.g.
|
|
a _Value_ to match) to complete.
|
|
|
|
When you select a field from the field name list and select a binary relation
|
|
(such as the equality relation ==) you will be given the opportunity to enter a
|
|
value, and possibly some range information.
|
|
|
|
_Value_::
|
|
You may enter an appropriate value in the _Value_ text box. The _Value_ will
|
|
also indicate the type of value for the _field name_ you have selected (like
|
|
character string).
|
|
|
|
_Predefined values_::
|
|
Some of the protocol fields have predefined values available, much like enum's
|
|
in C. If the selected protocol field has such values defined, you can choose one
|
|
of them here.
|
|
|
|
_Range_::
|
|
A range of integers or a group of ranges, such as `1-12` or `39-42,98-2000`.
|
|
|
|
_OK_::
|
|
When you have built a satisfactory expression click button:[OK] and a filter string
|
|
will be built for you.
|
|
|
|
_Cancel_::
|
|
You can leave the ``Add Expression...'' dialog box without any effect by
|
|
clicking the button:[Cancel] button.
|
|
|
|
[[ChWorkDefineFilterSection]]
|
|
|
|
=== Defining and saving filters
|
|
|
|
You can define filters with Wireshark and give them labels for later use. This
|
|
can save time in remembering and retyping some of the more complex filters you
|
|
use.
|
|
|
|
To define a new filter or edit an existing one, select menu:Capture[Capture
|
|
Filters...] or menu:Analyze[Display Filters...]. Wireshark will then pop up the
|
|
Filters dialog as shown in
|
|
<<FiltersDialog>>.
|
|
|
|
The mechanisms for defining and saving capture filters and display filters are
|
|
almost identical. Both will be described here but the differences between these two
|
|
will be marked as such.
|
|
|
|
[WARNING]
|
|
====
|
|
You must use button:[Save] to save your filters permanently. button:[OK] or
|
|
button:[Apply] will not save the filters and they will be lost when you close
|
|
Wireshark.
|
|
====
|
|
|
|
[[FiltersDialog]]
|
|
|
|
.The ``Capture Filters'' and ``Display Filters'' dialog boxes
|
|
image::wsug_graphics/ws-filters.png[]
|
|
|
|
_New_::
|
|
This button adds a new filter to the list of filters. The currently entered
|
|
values from Filter name and Filter string will be used. If any of these fields
|
|
are empty, it will be set to ``new''.
|
|
|
|
|
|
_Delete_::
|
|
This button deletes the selected filter. It will be greyed out, if no filter is
|
|
selected.
|
|
|
|
|
|
_Filter_::
|
|
You can select a filter from this list (which will fill in the filter name and
|
|
filter string in the fields down at the bottom of the dialog box).
|
|
|
|
|
|
_Filter name:_::
|
|
You can change the name of the currently selected filter here.
|
|
+
|
|
The filter name will only be used in this dialog to identify the filter for your
|
|
convenience, it will not be used elsewhere. You can add multiple filters with
|
|
the same name, but this is not very useful.
|
|
|
|
_Filter string:_::
|
|
You can change the filter string of the currently selected filter here. Display
|
|
Filter only: the string will be syntax checked while you are typing.
|
|
|
|
_Add Expression..._::
|
|
Display Filter only: This button brings up the Add Expression dialog box which
|
|
assists in building filter strings. You can find more information about the Add
|
|
Expression dialog in <<ChWorkFilterAddExpressionSection>>
|
|
|
|
_OK_::
|
|
Display Filter only: This button applies the selected filter to the current
|
|
display and closes the dialog.
|
|
|
|
_Apply_::
|
|
Display Filter only: This button applies the selected filter to the current
|
|
display, and keeps the dialog open.
|
|
|
|
_Save_::
|
|
Save the current settings in this dialog. The file location and format is
|
|
explained in <<AppFiles>>.
|
|
|
|
_Close_::
|
|
Close this dialog. This will discard unsaved settings.
|
|
|
|
[[ChWorkDefineFilterMacrosSection]]
|
|
|
|
=== Defining and saving filter macros
|
|
|
|
You can define filter macros with Wireshark and give them labels for later use.
|
|
This can save time in remembering and retyping some of the more complex filters
|
|
you use.
|
|
|
|
// XXX - add an explanation of this.
|
|
|
|
[[ChWorkFindPacketSection]]
|
|
|
|
=== Finding packets
|
|
|
|
You can easily find packets once you have captured some packets or have read in
|
|
a previously saved capture file. Simply select the _Find Packet..._ menu item
|
|
from the _Edit_ menu. Wireshark will pop up the dialog box shown in
|
|
<<ChWorkFindPacketDialog>>.
|
|
|
|
==== The ``Find Packet'' dialog box
|
|
|
|
[[ChWorkFindPacketDialog]]
|
|
|
|
.The ``Find Packet'' dialog box
|
|
image::wsug_graphics/ws-find-packet.png[]
|
|
|
|
You might first select the kind of thing to search for:
|
|
|
|
* _Display filter_
|
|
+
|
|
Simply enter a display filter string into the _Filter:_ field, select a direction, and click on OK.
|
|
+
|
|
For example, to find the three way handshake for a connection from host 192.168.0.1, use the following filter string:
|
|
----
|
|
ip.src==192.168.0.1 and tcp.flags.syn==1
|
|
----
|
|
For more details on display filters, see <<ChWorkDisplayFilterSection>>
|
|
|
|
* _Hex Value_
|
|
+
|
|
Search for a specific byte sequence in the packet data.
|
|
+
|
|
For example, use ``00:00'' to find the next packet including two null bytes in the packet data.
|
|
|
|
* _String_
|
|
+
|
|
Find a string in the packet data, with various options.
|
|
+
|
|
The value to be found will be syntax checked while you type it in. If the syntax
|
|
check of your value succeeds, the background of the entry field will turn green,
|
|
if it fails, it will turn red.
|
|
|
|
You can choose the search direction:
|
|
|
|
* _Up_
|
|
+
|
|
Search upwards in the packet list (decreasing packet numbers).
|
|
|
|
* _Down_
|
|
+
|
|
Search downwards in the packet list (increasing packet numbers).
|
|
|
|
==== The ``Find Next'' command
|
|
|
|
``Find Next'' will continue searching with the same options used in the last
|
|
``Find Packet''.
|
|
|
|
==== The ``Find Previous'' command
|
|
|
|
``Find Previous'' will do the same thing as ``Find Next'', but in the reverse
|
|
direction.
|
|
|
|
[[ChWorkGoToPacketSection]]
|
|
|
|
=== Go to a specific packet
|
|
|
|
You can easily jump to specific packets with one of the menu items in the Go menu.
|
|
|
|
==== The ``Go Back'' command
|
|
|
|
Go back in the packet history, works much like the page history in current web browsers.
|
|
|
|
==== The ``Go Forward'' command
|
|
|
|
Go forward in the packet history, works much like the page history in current web browsers.
|
|
|
|
==== The ``Go to Packet'' dialog box
|
|
|
|
[[ChWorkGoToPacketDialog]]
|
|
|
|
.The ``Go To Packet'' dialog box
|
|
image::wsug_graphics/ws-goto-packet.png[]
|
|
|
|
This dialog box will let you enter a packet number. When you press button:[OK],
|
|
Wireshark will jump to that packet.
|
|
|
|
==== The ``Go to Corresponding Packet'' command
|
|
|
|
If a protocol field is selected which points to another packet in the capture
|
|
file, this command will jump to that packet.
|
|
|
|
As these protocol fields now work like links (just as in your Web browser), it's
|
|
easier to simply double-click on the field to jump to the corresponding field.
|
|
|
|
==== The ``Go to First Packet'' command
|
|
|
|
This command will simply jump to the first packet displayed.
|
|
|
|
==== The ``Go to Last Packet'' command
|
|
|
|
This command will simply jump to the last packet displayed.
|
|
|
|
[[ChWorkMarkPacketSection]]
|
|
|
|
=== Marking packets
|
|
|
|
You can mark packets in the ``Packet List'' pane. A marked packet will be shown
|
|
with black background, regardless of the coloring rules set. Marking a packet
|
|
can be useful to find it later while analyzing in a large capture file.
|
|
|
|
The packet marks are not stored in the capture file or anywhere else. All
|
|
packet marks will be lost when you close the capture file.
|
|
|
|
You can use packet marking to control the output of packets when saving,
|
|
exporting, or printing. To do so, an option in the packet range is available,
|
|
see <<ChIOPacketRangeSection>>.
|
|
|
|
There are three functions to manipulate the marked state of a packet:
|
|
|
|
* _Mark packet (toggle)_ toggles the marked state of a single packet.
|
|
|
|
* _Mark all displayed packets_ set the mark state of all displayed packets.
|
|
|
|
* _Unmark all packets_ reset the mark state of all packets.
|
|
|
|
These mark functions are available from the ``Edit'' menu, and the ``Mark packet
|
|
(toggle)'' function is also available from the pop-up menu of the ``Packet
|
|
List'' pane.
|
|
|
|
[[ChWorkIgnorePacketSection]]
|
|
|
|
=== Ignoring packets
|
|
|
|
You can ignore packets in the ``Packet List'' pane. Wireshark will then pretend
|
|
that this packets does not exist in the capture file. An ignored packet will be
|
|
shown with white background and gray foreground, regardless of the coloring
|
|
rules set.
|
|
|
|
The packet ignored marks are not stored in the capture file or anywhere else.
|
|
All ``packet ignored'' marks will be lost when you close the capture file.
|
|
|
|
There are three functions to manipulate the ignored state of a packet:
|
|
|
|
* _Ignore packet (toggle)_ toggles the ignored state of a single packet.
|
|
|
|
* _Ignore all displayed packets_ set the ignored state of all displayed packets.
|
|
|
|
* _Un-Ignore all packets_ reset the ignored state of all packets.
|
|
|
|
These ignore functions are available from the ``Edit'' menu, and the ``Ignore
|
|
packet (toggle)'' function is also available from the pop-up menu of the
|
|
``Packet List'' pane.
|
|
|
|
[[ChWorkTimeFormatsSection]]
|
|
|
|
=== Time display formats and time references
|
|
|
|
While packets are captured, each packet is timestamped. These timestamps will be
|
|
saved to the capture file, so they will be available for later analysis.
|
|
|
|
A detailed description of timestamps, timezones and alike can be found at:
|
|
<<ChAdvTimestamps>>.
|
|
|
|
The timestamp presentation format and the precision in the packet list can be
|
|
chosen using the View menu, see <<ChUseWiresharkViewMenu>>.
|
|
|
|
The available presentation formats are:
|
|
|
|
* _Date and Time of Day: 1970-01-01 01:02:03.123456_ The absolute date and time
|
|
of the day when the packet was captured.
|
|
|
|
* _Time of Day: 01:02:03.123456_ The absolute time of the day when the packet
|
|
was captured.
|
|
|
|
* _Seconds Since Beginning of Capture: 123.123456_ The time relative to the
|
|
start of the capture file or the first ``Time Reference'' before this packet
|
|
(see <<ChWorkTimeReferencePacketSection>>).
|
|
|
|
* _Seconds Since Previous Captured Packet: 1.123456_ The time relative to the
|
|
previous captured packet.
|
|
|
|
* _Seconds Since Previous Displayed Packet: 1.123456_ The time relative to the
|
|
previous displayed packet.
|
|
|
|
* _Seconds Since Epoch (1970-01-01): 1234567890.123456_ The time relative to
|
|
epoch (midnight UTC of January 1, 1970).
|
|
|
|
The available precisions (aka. the number of displayed decimal places) are:
|
|
|
|
* _Automatic_ The timestamp precision of the loaded capture file format will be
|
|
used (the default).
|
|
|
|
* _Seconds, Deciseconds, Centiseconds, Milliseconds, Microseconds or
|
|
Nanoseconds_ The timestamp precision will be forced to the given setting. If
|
|
the actually available precision is smaller, zeros will be appended. If the
|
|
precision is larger, the remaining decimal places will be cut off.
|
|
|
|
Precision example: If you have a timestamp and it's displayed using, ``Seconds
|
|
Since Previous Packet'', : the value might be 1.123456. This will be displayed
|
|
using the ``Automatic'' setting for libpcap files (which is microseconds). If
|
|
you use Seconds it would show simply 1 and if you use Nanoseconds it shows
|
|
1.123456000.
|
|
|
|
[[ChWorkTimeReferencePacketSection]]
|
|
|
|
==== Packet time referencing
|
|
|
|
The user can set time references to packets. A time reference is the starting
|
|
point for all subsequent packet time calculations. It will be useful, if you
|
|
want to see the time values relative to a special packet, e.g. the start of a
|
|
new request. It's possible to set multiple time references in the capture file.
|
|
|
|
The time references will not be saved permanently and will be lost when you
|
|
close the capture file.
|
|
|
|
Time referencing will only be useful if the time display format is set to
|
|
``Seconds Since Beginning of Capture''. If one of the other time display formats
|
|
are used, time referencing will have no effect (and will make no sense either).
|
|
|
|
To work with time references, choose one of the menu:Time Reference[] items in
|
|
the menu:Edit[] menu or from the pop-up menu of the ``Packet List'' pane. See
|
|
<<ChUseEditMenuSection>>.
|
|
|
|
* _Set Time Reference (toggle)_ Toggles the time reference state of the
|
|
currently selected packet to on or off.
|
|
|
|
* _Find Next_ Find the next time referenced packet in the ``Packet List'' pane.
|
|
|
|
* _Find Previous_ Find the previous time referenced packet in the ``Packet
|
|
List'' pane.
|
|
|
|
[[ChWorkTimeReference]]
|
|
|
|
.Wireshark showing a time referenced packet
|
|
image::wsug_graphics/ws-time-reference.png[]
|
|
|
|
A time referenced packet will be marked with the string $$*REF*$$ in the Time
|
|
column (see packet number 10). All subsequent packets will show the time since
|
|
the last time reference.
|
|
|
|
++++++++++++++++++++++++++++++++++++++
|
|
<!-- End of WSUG Chapter Work -->
|
|
++++++++++++++++++++++++++++++++++++++
|