RLOGIN(1) BSD General Commands Manual RLOGIN(1)


rlogin — remote login


rlogin [−468DEd] [−e char] [−i localname] [−l username] host


The rlogin utility starts a terminal session on a remote host host.

The rlogin utility first attempts to use the Kerberos authorization mechanism, described below. If the remote host does not support Kerberos the standard Berkeley rhosts authorization mechanism is used.

The following options are available:


Use IPv4 addresses only.


Use IPv6 addresses only.


Allow an eight-bit input data path at all times; otherwise parity bits are stripped except when the remote side’s stop and start characters are other than ^S/^Q.


Set the TCP_NODELAY socket option which can improve interactive response at the expense of increased network load.


Stop any character from being recognized as an escape character. When used with the −8 option, this provides a completely transparent connection.


Turn on socket debugging (see setsockopt(2)) on the TCP sockets used for communication with the remote host.


Allow user specification of the escape character, which is ’’~’’ by default. This specification may be as a literal character, or as an octal value in the form \nnn.


Allow the caller to specify a different local name to be used for authentication. This option is restricted to processes with uid 0.


Specify a different username for the remote login. If this option is not specified, your local username will be used.

A line of the form ’’⟨

escape char ⟩ .’’ disconnects from the remote host. Similarly, the line ’’⟨
escape char ⟩ ^Z’’ will suspend the rlogin session, and ’’⟨
escape char ⟩ ⟨
delayed-suspend char ⟩ ’’ suspends the send portion of the rlogin session, but allows output from the remote system. By default, the tilde (’’~’’) character is the escape character, and normally control-Y (’’^Y’’) is the delayed-suspend character.

All echoing takes place at the remote site, so that (except for delays) the rlogin is transparent. Flow control via ^S/^Q and flushing of input and output on interrupts are handled properly.


Each user may have a private authorization list in the file .klogin in their home directory. Each line in this file should contain a Kerberos principal name of the form principal.instance@realm. If the originating user is authenticated to one of the principals named in .klogin, access is granted to the account. The principal accountname.@localrealm is granted access if there is no .klogin file. Otherwise a login and password will be prompted for on the remote machine as in login(1). To avoid certain security problems, the .klogin file must be owned by the remote user.

If Kerberos authentication fails, a warning message is printed and the standard Berkeley rlogin is used instead.


The following environment variable is utilized by rlogin:


Determines the user’s terminal type.


login(1), rsh(1), telnet(1), setsockopt(2), kerberos(3), krb_realmofhost(3), krb_sendauth(3), ruserok(3), tty(4), auth.conf(5), hosts(5), hosts.equiv(5), rlogind(8), rshd(8)



The rlogin command appeared in 4.2BSD.

IPv6 support was added by WIDE/KAME project.


The rlogin utility will be replaced by telnet(1) in the near future.

More of the environment should be propagated.

BSD September 26, 2003 BSD