inetd daemon

Introducing inetd

When your Linux system is booted for the first time, the inetd daemon is started from one of the startup scripts. On Red Hat Linux 6.0 systems, this daemon is started from the script file:

Example

/etc/rc.d/init.d/inet

This script is symbolically linked from various other places including the following noteworthy links:

/etc/rc.d/rc3.d/S50inet

/etc/rc.d/rc5.d/S50inet

These links initiate inetd when the system is started in the usual run-level 3 or run-level 5 modes.

NOTE

A run-level is simply a systemwide mode of operation. Linux supports several of these levels. See the init(8) man page for a full discussion of this. Run-level 3 is normally the run-level used when X Window is not used on a Linux system. Run-level 5 is usually used to automatically invoke the X Window server on the console. Note that this is simply a convention and your system conventions might differ. Other Linux distributions will have various other clever scripts and filenames to accomplish the same thing.

When the inetd daemon is started for the first time, it must know what Internet services it must listen for and what servers to pass the request off to when a request arrives. This is defined within the startup file /etc/inetd.conf.

See the sample /etc/inetd.conf file

NOTE

If you are using a company, university, or other shared Linux host, you might find that the /etc/inetd.conf file has been stripped down for security purposes.

Many sites eliminate nonessential services to avoid vulnerabilities in network attacks. Some sites might even eliminate running inetd completely. If this is the case, you will need to coordinate your efforts with the people looking after the security for the host involved.