Provided by: kerberos4kth-servers_1.2.2-11.3ubuntu4_i386
rlogind - remote login server
rlogind [-ailnkvxD] [-p portnumber] [-L /bin/login]
Rlogind is the server for the rlogin(1) program. The server provides a
remote login facility with kerberos-based authentication or traditional
pseudo-authentication with privileged port numbers from trusted hosts.
Options supported by rlogind:
-a No-op. For backwards compatibility. Hostnames are always
-l Prevent any authentication based on the user’s “.rhosts” file,
unless the user is logging in as the superuser.
-n Disable keep-alive messages.
-k Enable kerberos authentication.
-i Do not expect to be spawned by inetd and create a socket and
listen on it yourself.
Specifies the port number it should listen on in case the
-i flag has been given.
-v Vacuous, echo "Remote host requires Kerberos authentication" and
-x Provides an encrypted communications channel. This options
requires the -k flag.
Specify pathname to an alternative login program.
-D Use the TCP nodelay option (see setsockopt(2)).
When a service request is received, rlogind verifies the kerberos ticket
supplied by the user.
For non-kerberised connections, the following protocol is initiated:
1. The server checks the client’s source port. If the port is not in
the range 512-1023, the server aborts the connection.
2. The server checks the client’s source address and requests the
corresponding host name (see gethostbyaddr(3), hosts(5) and
named(8)). If the hostname cannot be determined, the dot-notation
representation of the host address is used. The addresses for the
hostname are requested, verifying that the name and address
correspond. Normal authentication is bypassed if the address
Once the source port and address have been checked, rlogind proceeds with
the authentication process described in rshd(8).
It then allocates a pseudo terminal (see pty(4)), and manipulates file
descriptors so that the slave half of the pseudo terminal becomes the
stdin, stdout, and stderr for a login process. The login process is an
instance of the login(1) program, invoked with the -f option if
authentication has succeeded. If automatic authentication fails, the
user is prompted to log in as if on a standard terminal line.
The parent of the login process manipulates the master side of the pseudo
terminal, operating as an intermediary between the login process and the
client instance of the rlogin program. In normal operation, the packet
protocol described in pty(4) is invoked to provide ‘^S/^Q’ type
facilities and propagate interrupt signals to the remote programs. The
login process propagates the client terminal’s baud rate and terminal
type, as found in the environment variable, ‘TERM’; see environ(7). The
screen or window size of the terminal is requested from the client, and
window size changes from the client are propagated to the pseudo
Transport-level keepalive messages are enabled unless the -n option is
present. The use of keepalive messages allows sessions to be timed out
if the client crashes or becomes unreachable.
All initial diagnostic messages are indicated by a leading byte with a
value of 1, after which any network connections are closed. If there are
no errors before login is invoked, a null byte is returned as in
indication of success.
A fork by the server failed.
login(1), ruserok(3), rshd(8)
A more extensible protocol should be used.
The rlogind command appeared in 4.2BSD.