11.12.07
tcpdump
This site has some very interesting uses of tcpdump. In particular I’ve used this one a couple of times:
tcpdump -i eth0 '(tcp[13] = 2 and dst host myHost) or (tcp[13] = 18 and \ src host myHost)'
It matches SYN packets sent to myHost and SYN/ACK packets sent back.
