NAME

inetd − Internet superdaemon

USAGE

/etc/inetd

DESCRIPTION

The inetd is a server-manager that invokes internet services, such as ftpd(8C) or rlogind(8C), as necessary.  Since it is a single process, inetd efficiently manages all types of internet connections. 

The following servers and daemons can only be invoked by inetd.  (This represents a change from the SR9.0 DOMAIN/IX convention). 

/etc/ftpd DARPA File Transfer Protocol daemon

/etc/rexecd Remote execution server

/etc/rlogind Remote log-in daemon

/etc/rshd Remote Shell server

/etc/telnetd DARPA TELNET protocol server

The inetd configuration file, /etc/inetd.conf is, in nearly all installations, a link to ‘node_data/etc.inetd.conf, a per-node file.  Inetd reads this file at boot time and, in some cases, after it gets a hangup signal.  Details about this file may be found under inetd.conf(4). 

When a connection-oriented service such as telnet(1) is requested, inetd creates a process running the necessary server and passes it the connection as standard input (file descriptor 0).  The server calls getpeername(2), which returns the source host and port. 

When a datagram arrives for a datagram-oriented service, inetd creates a process running the appropriate datagram-oriented server, and then passes it the socket (on which the pending datagram is being held) as file descriptor 0. 

If the server is “single-threaded,” it simply takes over the socket.  If the server is “multi-threaded,” it connects directly to the peer, freeing up the socket for continued use by inetd.  The distinction between single- and multi-threaded servers must be noted, using the “wait” and “nowait” keywords, respectively, in ‘node_data/etc.inetd.conf. 

If inetd encounters a serious error (e.g., unknown service, socket I/O error, incorrect server pathname), it attempts to log the error via syslog(8).  We recommend that you run a syslog daemon on your node, especially if you are debugging a new server. 

EXAMPLE

We recommend invoking inetd in background mode via the /etc/rc Shell script.  If you include the lines if [ -f /etc/inetd ]; then  /etc/inetd & fi in your node’s ‘node_data/etc.rc file, the /etc/run_rc program will start inetd at boot time (after first checking to see if the file exists).  Old versions of ‘node_data/etc.rc typically include lines that start individual internet server daemons.  If your node’s copy of ‘node_data/etc.rc includes such lines, remove them.  We copy in a correct version of /etc/rc, including these lines, on installation (unless you have a diskless node).

FILES

/sys/node_data/inetd.conf inetd configuration file

/etc/services internet services database

RELATED INFORMATION

inetd.conf(4) services(5) protocols(5) rc(8) syslog(8) ftpd(8C) rexecd(8C) rlogind(8C) rshd(8C) telnetd(8C) Managing TCP/IP-Based Communications Products