rlogind(1Mtcp)

rlogind -- remote login server

Synopsis

in.rlogind [-a] [-l] [-n]

Description

The rlogind command is the server for the rlogin(1tcp) program. The server provides a remote login facility with authentication based on privileged port numbers.

Options

rlogind understands the following options:

-a: Verify the address of the remote host.
-l: Prevent authentication based on a user's .rhosts file unless the user is logging in as root.
-n: Disable transport-level keepalive messages. Keepalive messages allows sessions to be timed out if the client crashes or becomes unreachable.

Usage

rlogind is invoked by inetd(1Mtcp) when a remote login connection is established, and executes the following protocol:

The server checks the remote client's source port. If the port is not in the range 512-1023, the server aborts the connection.
The server checks the remote client's source address. If an entry for the client exists in both /etc/hosts and /etc/hosts.equiv or ~/.rhosts, a user logging in from the client is not prompted for a password. If the address is associated with a host for which no corresponding entry exists in /etc/hosts, the user is prompted for a password, regardless of whether or not an entry for the remote client is present in /etc/hosts.equiv or ~/.rhosts (see hosts(4tcp), hosts.equiv(4tcp) and rhosts(4tcp)).

Once the source port and address have been checked, rlogind invokes a login process. The login process is an instance of the in.login scheme, which is based on login(1). The login process is invoked with the -R option to indicate that it is originated by rlogind. The login process proceeds with the authentication process as described in rshd(1Mtcp), but if automatic authentication fails, it reprompts the user to login as one finds on a standard terminal line.

In normal operation, a packet protocol is invoked to provide <ctrl><S> / <ctrl><Q> type facilities and propagate interrupt signals to the remote commands. The login process propagates the client terminal's baud rate and terminal type, as found in the environment variable, TERM; see environ(5).

Diagnostics

All diagnostic messages are returned on the connection associated with the stderr, after which any network connections are closed. An error is indicated by a leading byte with a value of 1.

Hostname for your address unknown.: No entry in the host name database existed for the client's machine.
Try again.: A fork by the server failed.
/usr/bin/sh: ...: The user's login shell could not be started.

References

hosts(4tcp), hosts.equiv(4tcp), inetd(1Mtcp), inetd.conf(4tcp)

Notices

The authentication procedure used here assumes the integrity of each client machine and the connecting medium. This is insecure, but is useful in an ``open'' environment.

A facility to allow all data exchanges to be encrypted should be present.