man dsniff (Administration système) - dsniff - password sniffer


dsniff - password sniffer


dsniff [-c] [-d] [-m] [-n] [-i interface | -p pcapfile] [-s snaplen] [-f services] [-t trigger[,...]]] [-r|-w savefile] [expression]


dsniff is a password sniffer which handles FTP, Telnet, SMTP, HTTP, POP, poppass, NNTP, IMAP, SNMP, LDAP, Rlogin, RIP, OSPF, PPTP MS-CHAP, NFS, VRRP, YP/NIS, SOCKS, X11, CVS, IRC, AIM, ICQ, Napster, PostgreSQL, Meeting Maker, Citrix ICA, Symantec pcAnywhere, NAI Sniffer, Microsoft SMB, Oracle SQL*Net, Sybase and Microsoft SQL protocols.

dsniff automatically detects and minimally parses each application protocol, only saving the interesting bits, and uses Berkeley DB as its output file format, only logging unique authentication attempts. Full TCP/IP reassembly is provided by libnids(3).

I wrote dsniff with honest intentions - to audit my own network, and to demonstrate the insecurity of cleartext network protocols. Please do not abuse this software.


Perform half-duplex TCP stream reassembly, to handle asymmetrically routed traffic (such as when using arpspoof(8) to intercept client traffic bound for the local gateway).
Enable debugging mode.
Enable automatic protocol detection.
Do not resolve IP addresses to hostnames.
-i interface
Specify the interface to listen on.
-p pcapfile
Rather than processing the contents of packets observed upon the network process the given PCAP capture file.
-s snaplen
Analyze at most the first snaplen bytes of each TCP connection, rather than the default of 1024.
-f services
Load triggers from a services file.
-t trigger[,...]
Load triggers from a comma-separated list, specified as port/proto=service (e.g. 80/tcp=http).
-r savefile
Read sniffed sessions from a savefile created with the -w option.
-w file
Write sniffed sessions to savefile rather than parsing and printing them out.
Specify a tcpdump(8) filter expression to select traffic to sniff.

On a hangup signal dsniff will dump its current trigger table to


Default trigger table
Network protocol magic



Dug Song <>


dsniff's automatic protocol detection feature is based on the classic file(1) command by Ian Darwin, and shares its historical limitations and bugs.