SERVICES(5)

NAME
services - service name database

DESCRIPTION
The services file contains information regarding the known services available in the Internet. For each service, a single line should be present with the following information:

    official service name
    port number
    protocol name
    aliases

Items are separated by any number of blanks and/or tab characters. The port number and protocol name are considered a single item; a slash (‘/’) is used to separate the port and protocol (e.g., “512/tcp”).

A hash mark (‘#’) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by the routines which search the file.

Service names may contain any printable character other than a field delimiter, newline, or comment character.

To protect service ports from being used for dynamic port assignment, rc(8) reads services at boot and uses the contents to populate net.inet.tcp.baddynamic and net.inet.udp.baddynamic.

While it is the policy of IANA to assign a single well-known port number for both TCP and UDP, to avoid reducing the dynamic port range unnecessarily, the unused entries are not always listed in services.

FILES
/etc/services

SEE ALSO
getservent(3)

HISTORY
The services file format appeared in 4.2BSD.

BUGS
A name server should be used instead of a static file. Lines in /etc/services are limited to BUFSIZ characters (currently 1024). Longer lines will be ignored.