The below table lists common IP protocols and their well-known numbers. The authoritave list can be found on the IANA website here Protocol Number Protocol 1 ICMP 2 IGMP 6 TCP 17 UDP 41 IPv6 in IP Tunnel 47 GRE 50 ESP 51 AH 88 EIGRP 89 OSPF 103 PIM 112 VRRP 115 L2TP
