editcap



EDITCAP(1)               The Ethereal Network Analyzer              EDITCAP(1)




NAME

       editcap - Edit and/or translate the format of capture files


SYNOPSYS

       editcap [ -c packets per file] [ -E error probability] [ -F file for-
       mat ] [ -h ] [ -r ] [ -s snaplen ] [ -t time adjustment ] [ -T encapsu-
       lation type ] [ -v ] infile outfile [ record#[-record#] ... ]


DESCRIPTION

       Editcap is a program that reads a saved capture file and writes some or
       all of the packets in that capture file to another capture file.  Edit-
       cap knows how to read libpcap capture files, including those of tcp-
       dump, Ethereal, and other tools that write captures in that format.

       Editcap can read / import the following file formats:

       * libpcap/WinPcap, tcpdump and various other tools using tcpdump’s cap-
       ture format
       * snoop and atmsnoop
       * Shomiti/Finisar Surveyor captures
       * Novell LANalyzer captures
       * Microsoft Network Monitor captures
       * AIX’s iptrace captures
       * Cinco Networks NetXRay captures
       * Network Associates Windows-based Sniffer captures
       * Network General/Network Associates DOS-based Sniffer (compressed or
       uncompressed) captures
       * AG Group/WildPackets EtherPeek/TokenPeek/AiroPeek/EtherHelp/Packet-
       Grabber captures
       * RADCOM’s WAN/LAN analyzer captures
       * Network Instruments Observer version 9 captures
       * Lucent/Ascend router debug output
       * files from HP-UX’s nettl
       * Toshibas ISDN routers dump output
       * the output from i4btrace from the ISDN4BSD project
       * traces from the EyeSDN USB S0.
       * the output in IPLog format from the Cisco Secure Intrusion Detection
       System
       * pppd logs (pppdump format)
       * the output from VMS’s TCPIPtrace/TCPtrace/UCX$TRACE utilities
       * the text output from the DBS Etherwatch VMS utility
       * Visual Networks’ Visual UpTime traffic capture
       * the output from CoSine L2 debug
       * the output from Accellent’s 5Views LAN agents
       * Endace Measurement Systems’ ERF format captures
       * Linux Bluez Bluetooth stack hcidump -w traces

       There is no need to tell Editcap what type of file you are reading; it
       will determine the file type by itself.  Editcap is also capable of
       reading any of these file formats if they are compressed using gzip.
       Editcap recognizes this directly from the file; the ’.gz’ extension is
       not required for this purpose.

       By default, it writes the capture file in libpcap format, and writes
       all of the packets in the capture file to the output file.  The -F flag
       can be used to specify the format in which to write the capture file;
       it can write the file in libpcap format (standard libpcap format, a
       modified format used by some patched versions of libpcap, the format
       used by Red Hat Linux 6.1, or the format used by SuSE Linux 6.3), snoop
       format, uncompressed Sniffer format, Microsoft Network Monitor 1.x for-
       mat, the format used by Windows-based versions of the Sniffer software,
       and the format used by Visual Networks’ software.

       A list of packet numbers can be specified on the command line; the
       packets with those numbers will not be written to the capture file,
       unless the -r flag is specified, in which case only those packets will
       be written to the capture file.  Ranges of packet numbers can be speci-
       fied as start-end, referring to all packets from start to end (removing
       them all if -r isn’t specified, including them all if -r is specified).

       If the -c flag is used to specify the amount of packets in a capture
       file, the output file will be created with a suffix -nnnnn. The suffix
       starts at 00000. No more then the specified number of packets are writ-
       ten in the output file before the next output file is opened.

       If the -s flag is used to specify a snapshot length, frames in the
       input file with more captured data than the specified snapshot length
       will have only the amount of data specified by the snapshot length
       written to the output file.  This may be useful if the program that is
       to read the output file cannot handle packets larger than a certain
       size (for example, the versions of snoop in Solaris 2.5.1 and Solaris
       2.6 appear to reject Ethernet frames larger than the standard Ethernet
       MTU, making them incapable of handling gigabit Ethernet captures if
       jumbo frames were used).

       If the -t flag is used to specify a time adjustment, the specified
       adjustment will be applied to all selected frames in the capture file.
       The adjustment is specified as [-]seconds[.fractional seconds].  For
       example, -t 3600 advances the timestamp on selected frames by one hour
       while -t -0.5 reduces the timestamp on selected frames by one-half sec-
       ond.  This feature is useful when synchronizing dumps collected on dif-
       ferent machines where the time difference between the two machines is
       known or can be estimated.

       If the -T flag is used to specify an encapsulation type, the encapsula-
       tion type of the output capture file will be forced to the specified
       type, rather than being the type appropriate to the encapsulation type
       of the input capture file.  Note that this merely forces the encapsula-
       tion type of the output file to be the specified type; the packet head-
       ers of the packets will not be translated from the encapsulation type
       of the input capture file to the specified encapsulation type (for
       example, it will not translate an Ethernet capture to an FDDI capture
       if an Ethernet capture is read and ’-T fddi’ is specified).

       If the -E flag is used to specify a probability (between 0.0 and 1.0
       inclusive), Editcap uses that probability to apply errors to each data
       byte in the file.  For instance, a probability of 0.02 means that each
       byte has a 2% chance of having an error.  This option is meant to be
       used for fuzz-testing protocol dissectors.


OPTIONS

       -c  Sets the number of packets per output file.

       -E  Sets the probabilty that bytes in the output file are randomly
           changed.

       -F  Sets the file format of the output capture file.

       -T  Sets the packet encapsulation type of the output capture file.

       -r  Causes the packets whose packet numbers are specified on the com-
           mand line to be written to the output capture file, and no other
           packets to be written to the output capture file.

       -v  Causes editcap to print a number of messages while it’s working.

       -s  Sets the snapshot length to use when writing the data.

       -t  Sets the time adjustment to use on selected frames.

       -h  Prints the version and options and exits.


EXAMPLES

       To see more detailed description of the options use:

           editcap -h

       To shrink the capture file by truncating the packets at 64 bytes and
       writing it as Sun snoop file use:

           editcap -s 64 -F snoop capture.pcap shortcapture.snoop

       To delete packet 1000 from the capture file use:

           editcap capture.pcap sans1000.pcap 1000

       To limit a capture file to packets from number 200 to 750 (inclusive)
       use:

           editcap -r capture.pcap small.pcap 200-750

       To get all packets from number 1-500 (inclusive) use:

           editcap -r capture.pcap 500.pcap 1-500

       or

           editcap capture.pcap 500.pcap 501-9999999

       To filter out packets 10 to 20 and 30 to 40 into a new file use:

           editcap capture.pcap selection.pcap 10-20 30-40

       To introduce 5% random errors in a capture file use:

         editcap -E 0.05 capture.pcap capture_error.pcap


SEE ALSO

       tcpdump(8), pcap(3), ethereal(1), mergecap(1)


NOTES

       Editcap is part of the Ethereal distribution.  The latest version of
       Ethereal can be found at http://www.ethereal.com.


AUTHORS

         Original Author
         -------- ------
         Richard Sharpe           <sharpe[AT]ns.aus.com>

         Contributors
         ------------
         Guy Harris               <guy[AT]alum.mit.edu>



0.10.14                           2005-12-26                        EDITCAP(1)

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