ettercap-common binary package in Ubuntu Precise i386

 Ettercap supports active and passive dissection of many protocols
 (even encrypted ones) and includes many feature for network and host
 analysis.
 .
 Data injection in an established connection and filtering (substitute
 or drop a packet) on the fly is also possible, keeping the connection
 synchronized.
 .
 Many sniffing modes are implemented, for a powerful and complete
 sniffing suite. It is possible to sniff in four modes: IP Based, MAC Based,
 ARP Based (full-duplex) and PublicARP Based (half-duplex).
 .
 Ettercap also has the ability to detect a switched LAN, and to use OS
 fingerprints (active or passive) to find the geometry of the LAN.
 .
 This package contains the Common support files, configuration files,
 plugins, and documentation. You must also install either
 ettercap-graphical or ettercap-text-only for the actual GUI-enabled
 or text-only ettercap executable, respectively.

Source package