xinetd

To control access to Internet services, use xinetd, which is a secure replacement for inetd. The xinetd daemon conserves system resources, provides access control and logging, and can be used to start special-purpose servers. xinetd can also be used to grant or deny access to particular hosts, provide service access at specific times, limit the rate of incoming connections, limit the load created by connections, and more.

xinetd runs constantly and listens on all ports for the services it manages. When a connection request arrives for one of its managed services, xinetd starts up the appropriate server for that service.

The configuration file for xinetd is /etc/xinetd.conf, but the file only contains a few defaults and an instruction to include the /etc/xinetd.d directory. To enable or disable an xinetd service, edit its configuration file in the /etc/xinetd.d directory. If the disable attribute is set to yes, the service is disabled. If the disable attribute is set to no, the service is enabled. You can edit any of the xinetd configuration files or change its enabled status using the Services Configuration Tool, ntsysv, or chkconfig. For a list of network services controlled by xinetd, review the contents of the /etc/xinetd.d directory with the command ls /etc/xinetd.d.