services File Format for TCP/IP

Purpose

Defines the sockets and protocols used for Internet services.

Description

The /etc/services file contains information about the known services used in the DARPA Internet network. Each service is listed on a single line corresponding to the form:

ServiceName PortNumber/ProtocolName Aliases

These fields contain the following information:

Item Description
ServiceName Specifies an official Internet service name.
PortNumber Specifies the socket port number used for the service.
ProtocolName Specifies the transport protocol used for the service.
Aliases Specifies a list of unofficial service names.

Items on a line are separated by spaces or tabs. Comments begin with a # (pound sign) and continue until the end of the line.

If you edit the /etc/services file, run the refresh -s inetd or kill -1 InetdPID command to inform the inetd daemon of the changes.

Examples

Entries in the services file for the inetd internal services may look like this:

echo          7/tcp
echo          7/udp
discard       9/tcp      sink null
discard       9/udp      sink null
daytime      13/tcp
daytime      13/udp
chargen      19/tcp      ttytst source
chargen      19/udp      ttytst source
ftp          21/tcp
time         37/tcp      timeserver
time         37/udp      timeserver