10.3 System Boot without
The /usr/sbin/inetd daemon provides Internet service management for a network. This daemon reduces system load by invoking other daemons only when they are needed and by providing several simple Internet services internally without invoking other daemons.
When the daemon starts, it reads its configuration information from the file specified in the Configuration File parameter. If the parameter is not specified, the inetd daemon reads its configuration information from the /etc/inetd.conf file. Once started, the inetd daemon listens for connections on certain Internet sockets in the /etc/inetd.conf and either handles the service request itself or invokes the appropriate server once a request on one of these sockets is received.
The /etc/inetd.conf file can be updated by using the System Management Interface Tool (SMIT), the System Resource Controller (SRC), or by editing the /etc/inetd.conf.
If you change the /etc/inetd.conf using SMIT, then the inetd daemon will be
refreshed automatically and will read the new /etc/inetd.conf file. If you
change the file using an editor, run the refresh -s inetd
or kill -1 InetdPID
commands to inform the inetd daemon of the changes to its
configuration file. There will not be any message if you use the kill
-1 command as shown in Figure 86.
Figure 86: Refreshing the inetd Daemon using Refresh or Kill
The inetd daemon is a subsystem that controls the following daemons (subservers):
The ftpd, rlogind, rexecd, rshd, talkd, telnetd, and uucpd daemons are started by default. The tftpd, fingerd, and comsat daemons are not started by default.
To start any one of them, remove the # sign in column one of the respective
entry in the /etc/inetd.conf file. You can check the details of subservers
started in inetd by using the lssrc -ls command
as shown in Figure 87.
Figure 87: Subservers Started in inetd
Use the command stopsrc -s inetd
to stop the inetd daemon as shown in
Figure 88: Stopping inetd
When the inetd daemon is stopped, the previously started subservers
processes are not affected. However, new service requests for the subservers
can no longer be satisfied. If you try to telnet
or ftp to the server with
inetd down, you will see messages as shown in Figure 89.
Figure 89: Telnet and FTP when inetd at Server is Down
In other words, though existing sessions are not affected when the inetd daemon is stopped. No new telnet and ftp session can be established without restarting the inetd daemon first.
10.5 The Portmap