TCPDUMP is loaded by default in most modern Linux distributions. If it isn't installed, you can get it from the URL in Section 5
TCPDUMP--
- Download "libpcap" and do the following commands:
"configure"
"make"
"make install"
"make install-man"
"make install-incl"
"cp libpcap/bpf/net/* /usr/include/net"
- Download "tcpdump" and do the following commands:
"configure"
"make"
"make install"
"make install-man"
- Now run "tcpdump" and watch it fly. Look at TCPDUMP's man page as you can send captures to a file, filter the traffic to only stuff you care upon based on source IP, destination IP, ports, UDP, TCP, etc.