protocols(4)protocols(4)NAMEprotocols - Defines the Internet protocols used on the local host
SYNOPSIS
/etc/protocols
DESCRIPTION
The /etc/protocols file contains information about the known protocols
used in the Internet. Each protocol is represented by a single line in
the protocols file. Each entry is of the form:
Name Number Aliases
The fields contain the following information: Official Internet proto‐
col name. Protocol number. Unofficial names used for the protocol.
Items on a line are separated by one or more spaces or tab characters.
Comments begin with the # (number sign), and routines that search the
protocols file do not interpret characters from the beginning of a com‐
ment to the end of the line. A protocol name can contain any printable
character except a field delimiter, newline character, or comment char‐
acter.
The lines in the file appear as follows:
# # Internet (IP) protocols # ip 0 IP # internet proto‐
col, pseudo protocol number icmp 1 ICMP # internet control
message protocol igmp 2 IGMP # internet group management
protocol ggp 3 GGP # gateway-gateway protocol tcp 6
TCP # transmission control protocol pup 12 PUP #
PARC universal packet protocol udp 17 UDP # user datagram
protocol hopopt 0 HOPOPT # hop-by-hop options
for ipv6 ipv6 41 IPV6 # ipv6 ipv6-route
43 IPV6-ROUTE # routing header for ipv6 ipv6-frag 44
IPV6-FRAG # fragment header for ipv6 esp 50 ESP
# encapsulating security payload ah 51 AH
# authentication header ipv6-icmp 58 IPV6-ICMP # icmp
for ipv6 ipv6-nonxt 59 IPV6-NONXT # no next header for
ipv6 ipv6-opts 60 IPV6-OPTS # destination options for
ipv6.oE
SEE ALSO
Functions: endprotoent(3), getprotobyname(3), getprotobynumber(3), get‐
protoent(3), setprotoent(3)protocols(4)