Protocol is a read-only Byte property that specifies the IP protocol supported for the Well Know Service host. Protocol can be one of the following values:
- 0 Reserved
- 1 ICMP Internet Control Message
- 2 IGMP Internet Group Management
- 3 GGP Gateway-to-Gateway
- 4 Unassigned
- 5 ST Stream
- 6 TCP Transmission Control
- 7 UCL UCL
- 8 EGP Exterior Gateway Protocol
- 9 IGP any private interior gateway
- 10 BBN-RCC-MON BBN RCC Monitoring
- 11 NVP-II Network Voice Protocol
- 12 PUP PUP
- 13 ARGUS ARGUS
- 14 EMCON EMCON
- 15 XNET Cross Net Debugger
- 16 CHAOS Chaos
- 17 UDP User Datagram
- 18 MUX Multiplexing
- 19 DCN-MEAS DCN Measurement Subsystems
- 20 HMP Host Monitoring
- 21 PRM Packet Radio Measurement
- 22 XNS-IDP XEROX NS IDP
- 23 TRUNK-1 Trunk-1
- 24 TRUNK-2 Trunk-2
- 25 LEAF-1 Leaf-1
- 26 LEAF-2 Leaf-2
- 27 RDP Reliable Data Protocol
- 28 IRTP Internet Reliable Transaction
- 29 ISO-TP4 ISO Transport Protocol Class 4
- 30 NETBLT Bulk Data Transfer Protocol
- 31 MFE-NSP MFE Network Services Protocol
- 32 MERIT-INP MERIT Internodal Protocol
- 33 SEP Sequential Exchange Protocol
- 34-60 Unassigned
- 61 any host internal protocol
- 62 CFTP CFTP
- 63 any local network
- 64 SAT-EXPAK SATNET and Backroom EXPAK
- 65 MIT-SUBNET MIT Subnet Support
- 66 RVD MIT Remote Virtual Disk Protocol
- 67 IPPC Internet Pluribus Packet Core
- 68 any distributed file system
- 69 SAT-MON SATNET Monitoring
- 70 Unassigned
- 71 IPCV Internet Packet Core Utility
- 72-75 Unassigned
- 76 BR-SAT-MON Backroom SATNET Monitoring
- 77 Unassigned
- 78 WB-MON WIDEBAND Monitoring
- 79 WB-EXPAK WIDEBAND EXPAK
- 80-254 Unassigned
- 255 Reserved