Appendix B: Common IP Protocol NumbersThese are some of the more common IP Protocols, for all follow the link after the table.Decimal Keyword Description Reference1 ICMP Internet Control Message RFC7922 IGMP Internet Group Management RFC11123 GGP Gateway-to-Gateway RFC8234 IP IP in IP (encapsulation) RFC20035 ST Stream RFC1190, RFC18196 TCP Transmission Control RFC7938 EGP Exterior Gateway Protocol RFC88817 UDP User Datagram RFC76847 GRE General RoutingEncapsulation50 ESP Encapsulation SecurityPayloadRFC240651 AH Authentication Header RFC2402108 IPComp I IP Payload CompressionProtocolRFC2393112 VRRP Virtual Router RedundancyProtocol115 L2TP Layer Two Tunneling ProtocolSource: http://www.iana.org/assignments/protocol-numbers
