protocols(4)

NAME

     protocols - protocol name database

SYNOPSIS

     /etc/inet/protocols

     /etc/protocols

DESCRIPTION

     The protocols file  is a local source of information regard-
     ing the known protocols used in the DARPA Internet. The pro-
     tocols file can be used in conjunction with  or  instead  of
     other    protocols   sources,   including   the   NIS   maps
     ``protcols.byname'' and "protocols.bynumber"  and  the  NIS+
     table       ``protocols''.       Programs       use      the
     getprotobyname(3SOCKET) routine to access this information.

     The protocols file has one line for each protocol. The  line
     has the following format:

     official-protocol-name protocol-number aliases

     Items are separated by any number  of  blanks  and/or  <TAB>
     characters.  A  `#'  indicates  the  beginning of a comment;
     characters up to the end of the line are not interpreted  by
     routines  which  search the file. Protocol names may contain
     any printable character other than a field delimiter,  <NEW-
     LINE>, or comment character.

EXAMPLES

     Example 1: A Sample Database

     The following is a sample database:

     #
     # Internet (IP) protocols
     #
     ip          0   IP          # internet protocol, pseudo protocol number
     icmp        1   ICMP        # internet control message protocol
     ggp         3   GGP         # gateway-gateway protocol
     tcp         6   TCP         # transmission control protocol
     egp         8   EGP         # exterior gateway protocol
     pup         12  PUP         # PARC universal packet protocol
     udp         17  UDP         # user datagram protocol

     #
     # Internet (IPv6) extension headers
     #
     hopopt      0   HOPOPT      # Hop-by-hop options for IPv6
     ipv6        41  IPv6        # IPv6 in IP encapsulation
     ipv6-route  43  IPv6-Route  # Routing header for IPv6
     ipv6-frag   44  IPv6-Frag   # Fragment header for IPv6
     esp         50  ESP         # Encap Security Payload for IPv6
     ah          51  AH          # Authentication Header for IPv6
     ipv6-icmp   58  IPv6-ICMP   # IPv6 internet control message protocol
     ipv6-nonxt  59  IPv6-NoNxt  # No next header extension header for IPv6
     ipv6-opts   60  IPv6-Opts   # Destination Options for IPv6

FILES

     /etc/nsswitch.conf
           configuration file for name-service switch

SEE ALSO

     getprotobyname(3SOCKET), nsswitch.conf(4)

NOTES

     /etc/inet/protocols is the official SVR4 name of the  proto-
     cols  file.  The symbolic link /etc/protocols exists for BSD
     compatibility.