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ipstrings

NAME

ipstrings - Reads strings from pcap dump files

SYNOPSIS

ipstrings [-cefimnprstwvz] [interface]

DESCRIPTION

ipstrings reads text strings from all traffic on a network interface or from a pcap format data file (produced by tcpdump and other programs).

OPTIONS

interface

Network interface to read data from.

-c <npacket>

Terminate program after reading <npacket> packets.

-e

Print source and destination ethernet address with each string.

-f

Filter incoming packets according to filter string. For example,

   ipstrings -f "host 137.99.17.17" eth0

will pass the string "host 137.99.17.17" to the pcap library's filter routine. Thus ipstrings will only see packets with 137.99.17.17 in one of the two ip addresses. The filter commands are extensive and are explained fully in the tcpdump man page.

-i

Print source and destination ip address with each string.

-m

Do not enter promiscuous mode when reading network interface.

-n <nchar>

Consider strings to be any set of printable characters (ASCII 32 to 126) <NCHAR> characters long or greater. When <NCHAR> is set to zero, then only those sets of printable characters which are terminated by an ASCII 0 are printed.

-p

Print protocol number, source and destination port number for packets for each string printed. If protocol number is not 6 or 17 (tcp or udp) then port values are printed as 0.

-r <dumpfile>

Reads network info from <dumpfile> instead of reading live from network. Such a dumpfile could have been produced by the programs ipstrings, tcpdump or ethereal (http://www.zing.org). You can read from standard input using '-' as the file name, this feature is provided by the pcap libarary.

-s <nlen>

Read no more than first <nlen> packet bytes. Default is 96, minimum is 68.

-t

Write packet time in format HH:MM:SS.SSSS for string printed.

-w <dumpfile>

Writes first <nlen> bytes of every packet to <dumpfile> in pcap format (see -s option about <nlen>). Can later be read by programs such as ipaudit, ipstrings, tcpdump or ethereal, Use '-' to write to standard out (this is a feature provided by the pcap library).

-v

Print version information.

-z

Write packet size in bytes (size of ip portion, does not include ethernet or other header).

INPUT EXAMPLES

To read strings from packets going by interface eth0
   ipstrings eth0

To read all strings from a pcap dump file 'pcap.dump'
   ipstrings -r pcap.dump

To read only for host 10.2.2.2
   ipstrings -r pcap.dump -f "host 10.2.2.2"

To read 'pcap.dump' only for host 10.2.2.2 and port 21 (ftp)
   ipstrings -r pcap.dump -f "host 10.2.2.2 and port 21"

To read gzip'ed 'pcap.dump.gz" for all hosts and only port 23 (telnet)
   zcat pcap.dump.gz | ipstrings -r- "port 23"

OUTPUT EXAMPLES

A short FTP session to 127.0.0.1 was captured in pcap.file. When we give the command
   ipstrings -i -rpcap.fil

the output is

   127.000.000.001 127.000.000.001   6     21   1323  220 bluebird FTP server (Versi
   127.000.000.001 127.000.000.001   6   1323     21  USER jibe
   127.000.000.001 127.000.000.001   6     21   1323  331 Password required for jibe
   127.000.000.001 127.000.000.001   6   1323     21  PASS xxxxxxxx
   127.000.000.001 127.000.000.001   6     21   1323  230 User jibe logged in.
   127.000.000.001 127.000.000.001   6   1323     21  SYST
   127.000.000.001 127.000.000.001   6     21   1323  215 UNIX Type: L8
   127.000.000.001 127.000.000.001   6   1323     21  QUIT
   127.000.000.001 127.000.000.001   6     21   1323  221-You have transferred 0 byt
   127.000.000.001 127.000.000.001   6     21   1323  221-Total traffic for this ses

The first two columns are the source and destination ip addresses. Column three is the protocol, in this example all are 6 meaning all packets are tcp. Columns four and five are the source and destination port numbers. Starting in the sixth column are the printable strings that were found in the packets.

BUGS

Report any to jon.rifkin@uconn.edu.

URL

http://www.sp.uconn.edu/~jrifkin/ipstrings/

VERSION

0.5 May 25, 2000

SEE ALSO

tcpdump(1) pcap(3) ipaudit(1)