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Files Reference

services File Format for TCP/IP


Defines the sockets and protocols used for Internet services.


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:

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.


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

Related Information

The getservent subroutine.

The /etc/inetd.conf file format.

Object Data Manager (ODM) Overview for Programmers in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs.

TCP/IP Daemons in AIX 5L Version 5.2 System Management Guide: Communications and Networks.

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