NAMEipstrings - Reads strings from pcap dump files
SYNOPSISipstrings [-cefimnprstwvz] [interface]
DESCRIPTIONipstrings reads text strings from all traffic on a network interface or from a pcap format data file (produced by tcpdump and other programs).
Network interface to read data from.
- -c <npacket>
Terminate program after reading <npacket> packets.
Print source and destination ethernet address with each string.
Filter incoming packets according to filter string. For example,
ipstrings -f "host 220.127.116.11" eth0
will pass the string "host 18.104.22.168" to the pcap library's filter routine. Thus ipstrings will only see packets with 22.214.171.124 in one of the two ip addresses. The filter commands are extensive and are explained fully in the tcpdump man page.
Note that if you are trying to observe vlan traffic with your filter, you will have to specify the 'vlan' filter before other filters. In fact if all your traffic was vlan tagged, the command above would filter out all traffic, because the 'vlan' specifier was not included. To see vlan traffic the example above would need to change to
ipaudit -f "vlan and host 126.96.36.199" eth0
Print source and destination ip address with each string.
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.
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
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.
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
Use '-' to write to standard out (this is a feature provided
by the pcap library).
Print version information.
Write packet size in bytes (size of ip portion, does not include
ethernet or other header).
To read strings from packets going by interface 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"
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.