Tcpdump

Various commands

• tcpdump 'tcp[13] & 2 != 0' = Catch all SYN packets
• tcpdump 'tcp[13] & 4 != 0' = Catch all RST packets
• tcpdump 'tcp[13] & 16 != 0' = Catch all ACK packets

The 2, 4 and 16 above correspond to the 13th byte in the TCP header and only grab packets that have a not zero 2nd bit there, matching thus different type of TCP packets.