D-Link DFL-700 - Manual (Page 131)

Appendix B: Common IP Protocol Numbers
These are some of the more common IP Protocols, for all follow the link after the table.
Decimal Keyword Description Reference
1 ICMP Internet Control Message RFC792
2 IGMP Internet Group Management RFC1112
3 GGP Gateway-to-Gateway RFC823
4 IP IP in IP (encapsulation) RFC2003
5 ST Stream RFC1190, RFC1819
6 TCP Transmission Control RFC793
8 EGP Exterior Gateway Protocol RFC888
17 UDP User Datagram RFC768
47 GRE General Routing
Encapsulation
50 ESP Encapsulation Security
Payload RFC2406
51 AH Authentication Header RFC2402
108 IPComp I IP Payload Compression
Protocol RFC2393
112 VRRP Virtual Router Redundancy
Protocol
115 L2TP Layer Two Tunneling Protocol
Source: http://www.iana.org/assignments/protocol-numbers