Tcpdump Filter - Macro

src 	Pertains to the source side of the connection (src host 1.1.1.1)
dst 	Pertains to the destination side of the connection (dst port 23)
host 	Used to identify a host IP number or name (host 1.2.3.4)
port 	Used to identify a port number or name (port 21)
net 	Used to identify a network address (src net 1.1)
tcp 	Specify TCP records only (tcp and port 21)
udp 	Specify UDP records only (udp and host 2.2.2.2)
icmp 	Specify ICMP records only (icmp and host 4.3.2.1)
ip 	Specify IP records only (ip)
= != > >= < <= and or not