Decimal    Keyword     Protocol
=======    =======     ==============
     0     HOPOPT      IPv6 Hop-by-Hop Option           
     1     ICMP        Internet Control Message          
     2     IGMP        Internet Group Management        
     3     GGP         Gateway-to-Gateway                
     4     IP          IP in IP (encapsulation)         
     5     ST          Stream                    
     6     TCP         Transmission Control              
     7     CBT         CBT                            
     8     EGP         Exterior Gateway Protocol    
     9     IGP         any private interior gateway        
                       (used by Cisco for their IGRP)
    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     3PC         Third Party Connect Protocol        
    35     IDPR        Inter-Domain Policy Routing Protocol
    36     XTP         XTP                                  
    37     DDP         Datagram Delivery Protocol           
    38     IDPR-CMTP   IDPR Control Message Transport Proto
    39     TP++        TP++ Transport Protocol              
    40     IL          IL Transport Protocol           
    41     ISATAP      ISATAP                             
    42     SDRP        Source Demand Routing Protocol      
    43     IPv6-Route  Routing Header for IPv6          
    44     IPv6-Frag   Fragment Header for IPv6         
    45     IDRP        Inter-Domain Routing Protocol  
    46     RSVP        Reservation Protocol          
    47     GRE         General Routing Encapsulation    
    48     MHRP        Mobile Host Routing Protocol
    49     BNA         BNA                         
    50     ESP         Encap Security Payload for IPv6  
    51     AH          Authentication Header for IPv6   
    52     I-NLSP      Integrated Net Layer Security  TUBA
    53     SWIPE       IP with Encryption                   
    54     NARP        NBMA Address Resolution Protocol 
    55     MOBILE      IP Mobility                      
    56     TLSP        Transport Layer Security Protocol  
                       using Kryptonet key management
    57     SKIP        SKIP                             
    58     IPv6-ICMP   ICMP for IPv6                    
    59     IPv6-NoNxt  No Next Header for IPv6          
    60     IPv6-Opts   Destination Options for IPv6     
    61                 any host internal protocol          
    62     CFTP        CFTP                           
    63                 any local network                   
    64     SAT-EXPAK   SATNET and Backroom EXPAK            
    65     KRYPTOLAN   Kryptolan                           
    66     RVD         MIT Remote Virtual Disk Protocol     
    67     IPPC        Internet Pluribus Packet Core        
    68                 any distributed file system         
    69     SAT-MON     SATNET Monitoring                    
    70     VISA        VISA Protocol                       
    71     IPCV        Internet Packet Core Utility         
    72     CPNX        Computer Protocol Network Executive 
    73     CPHB        Computer Protocol Heart Beat        
    74     WSN         Wang Span Network                    
    75     PVP         Packet Video Protocol                
    76     BR-SAT-MON  Backroom SATNET Monitoring           
    77     SUN-ND      SUN ND PROTOCOL-Temporary            
    78     WB-MON      WIDEBAND Monitoring                  
    79     WB-EXPAK    WIDEBAND EXPAK                       
    80     ISO-IP      ISO Internet Protocol                
    81     VMTP        VMTP                                
    82     SECURE-VMTP SECURE-VMTP                         
    83     VINES       VINES                                
    84     TTP         TTP                                  
    85     NSFNET-IGP  NSFNET-IGP                           
    86     DGP         Dissimilar Gateway Protocol    
    87     TCF         TCF                                 
    88     EIGRP       EIGRP                          
    89     OSPFIGP     OSPFIGP                     
    90     Sprite-RPC  Sprite RPC Protocol           
    91     LARP        Locus Address Resolution Protocol    
    92     MTP         Multicast Transport Protocol         
    93     AX.25       AX.25 Frames                        
    94     IPIP        IP-within-IP Encapsulation Protocol  
    95     MICP        Mobile Internetworking Control Pro.  
    96     SCC-SP      Semaphore Communications Sec. Pro.   
    97     ETHERIP     Ethernet-within-IP Encapsulation    
    98     ENCAP       Encapsulation Header        
    99                 any private encryption scheme       
   100     GMTP        GMTP                                
   101     IFMP        Ipsilon Flow Management Protocol  
   102     PNNI        PNNI over IP                      
   103     PIM         Protocol Independent Multicast 
   104     ARIS        ARIS                             
   105     SCPS        SCPS              
   106     QNX         QNX             
   107     A/N         Active Networks                   
   108     IPComp      IP Payload Compression Protocol  
   109     SNP         Sitara Networks Protocol         
   110     Compaq-Peer Compaq Peer Protocol               
   111     IPX-in-IP   IPX in IP               
   112     VRRP        Virtual Router Redundancy Protocol
   113     PGM         PGM Reliable Transport Protocol 
   114                 any 0-hop protocol                  
   115     L2TP        Layer Two Tunneling Protocol       
   116     DDX         D-II Data Exchange (DDX)          
   117     IATP        Interactive Agent Transfer Protocol 
   118     STP         Schedule Transfer Protocol           
   119     SRP         SpectraLink Radio Protocol      
   120     UTI         UTI           
   121     SMP         Simple Message Protocol           
   122     SM          SM               
   123     PTP         Performance Transparency Protocol  
   124     ISIS over IPv4              
   125     FIRE                     
   126     CRTP        Combat Radio Transport Protocol 
   127     CRUDP       Combat Radio User Datagram   
   128     SSCOPMCE                 
   129     IPLT                 
   130     SPS         Secure Packet Shield            
   131     PIPE        Private IP Encapsulation within IP      
   132     SCTP        Stream Control Transmission Protocol  
   133     FC          Fibre Channel                       
   134-254             Unassigned                          
   255                 Reserved