Binary package “libpcap0.8” in ubuntu lucid

system interface for user-level packet capture

 libpcap (Packet CAPture) provides a portable framework for low-level
 network monitoring. Applications include network statistics collection,
 security monitoring, network debugging, etc.
 .
 Since almost every system vendor provides a different interface for
 packet capture, and since there are several tools that require this
 functionality, we've created this system-independent API to ease in
 porting and to alleviate the need for several system-dependent packet
 capture modules in each application.