Editcap - Edit and/or translate the format of capture
files
SYNOPSYS
editcap [ -F file format ] [ -T encapsulation type ]
[ -r ] [ -v ] [ -s snaplen ] [ -h ] infile outfile
[ 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. Editcap knows how to read libpcap
capture files, including those of tcpdump. In addition,
Editcap can read capture files from snoop (including
Shomiti) and atmsnoop, LanAlyzer, Sniffer (compressed or
uncompressed), Microsoft Network Monitor, AIX's iptrace,
NetXray, Sniffer Pro, RADCOM's WAN/LAN analyzer,
Lucent/Ascend router debug output, HP-UX's nettl, and the
dump output from Toshiba's ISDN routers. 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 capa
ble of reading any of these file formats if they are com
pressed 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 for
mat in which to write the capture file; it can write the
file in libpcap format (standard libpcap format, a modi
fied 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 for
mat, Microsoft Network Monitor 1.x format, and the format
used by Windows-based versions of the Sniffer 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 cap
ture file. Ranges of packet numbers can be specified 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 -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 out
put 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
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 an encapsulation type,
the encapsulation 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 encapsulation type
of the output file to be the specified type; the packet
headers of the packets will not be translated from the
encapsulation type of the input capture file to the speci
fied encapsulation type (for example, it will not trans
late an Ethernet capture to an FDDI capture if an Ethernet
capture is read and '-T fddi' is specified).
OPTIONS
-F Sets the file format of the output capture file.
-T Sets the packet encapsulation type of the output cap
ture file.
-r Causes the packets whose packet numbers are specified
on the command line to be written to the output cap
ture 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.
-h Prints the version and options and exits.
SEE ALSO
tcpdump(8), pcap(3), ethereal(1)
NOTES
Editcap is part of the Ethereal distribution. The latest
version of Ethereal can be found at http://www.ethe
real.com.
AUTHORS
Original Author
-------- ------
Richard Sharpe <sharpe@ns.aus.com>
Contributors
------------
Guy Harris <guy@alum.mit.edu>
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