Tcpick Tcp Stream Sniffer and Connection Tracker


This is EXAMPLES, produced by makeinfo version 4.7 from

1 Examples of tcpick usage

1.1 connection status

Tcpick is a sniffer able to understand wich status has the connection
(SYN-SENT, SYN-RECEIVED and so on). To see the connection tracker in
action on eth0 simply type:

     # tcpick -i eth0 -C

   `-C' means "enable colors", and the output is very pretty.

   You will see something like this:

     23:07:42.672171  1      SYN-SENT >
     23:07:42.822239  2      SYN-SENT >
     23:07:42.826634  3      SYN-SENT >
     23:07:42.854681  4      SYN-SENT >
     23:07:43.084242  1      SYN-RECEIVED >
     23:07:43.087045  1      ESTABLISHED >
     23:07:44.061311  5      SYN-SENT >

1.2 display the payload and packet headers

It is very easy:

     # tcpick -i eth0 -C -yP -h -a

   `-yP' means "payload printable", `-h' means "header" and `-a' means
names resolution.  Unprintable carachters are displayed as dots.

1.3 display client data only of the first smtp connection

     # tcpick -i eth0 -C -bCU -T1 "port 25"

   `-bCU' means: display the rebuilded stream (`-b') only the client
side (`C') and unprintable carachters will be displayed as hexcode

   `T1' means: display only the first (1) connection.

   "port 25" is the filter.

1.4 download a file passively

Yeah! It is very a simple job:

   #tcpick -i eth0 -wR "port ftp-data"

   When the file has been completely transmitted (connection displayed
as "CLOSED")  check in the working directory: you will find some files
named like this:

     # ls *.tcpick

   Bingo! If you do `$ file *.tcpick' you will find that one of the two
is a a gzip archive or whatever you sniffed.

1.5 redirect the first connection to a software

You must choose between client or server side, because you don't want
both stream mixed in the standard output. It is a really simple job,
just type:

     # tcpick -i eth0 --pipe client "port 80" | gzip > http_response.gz
     # tcpick -i eth0 --pipe server "port 25" | nc 25

   Now, use your imagination and let me know what crazy experiments have
you done with tcpick ;^)

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