.\" Copyright (c) 1983, 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
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.\"    may be used to endorse or promote products derived from this software
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.\"	@(#)rlogin.1	8.1 (Berkeley) 6/6/93
.\" $FreeBSD: src/usr.bin/rlogin/rlogin.1,v 1.11.2.7 2002/06/21 15:28:48 charnier Exp $
.\" $DragonFly: src/usr.bin/rlogin/rlogin.1,v 1.3 2006/02/17 19:39:10 swildner Exp $
.\"
.Dd June 6, 1993
.Dt RLOGIN 1
.Os
.Sh NAME
.Nm rlogin
.Nd remote login
.Sh SYNOPSIS
.Ar rlogin
.Op Fl 468DEKLdx
.Op Fl e Ar char
.Op Fl i Ar localname
.Op Fl k Ar realm
.Op Fl l Ar username
.Ar host
.Sh DESCRIPTION
The
.Nm
utility starts a terminal session on a remote host
.Ar host  .
.Pp
The
.Nm
utility
first attempts to use the Kerberos authorization mechanism, described below.
If the remote host does not support Kerberos the standard Berkeley
.Pa rhosts
authorization mechanism is used.
The options are as follows:
.Bl -tag -width flag
.It Fl 4
Use IPv4 addresses only.
.It Fl 6
Use IPv6 addresses only.
.It Fl 8
The
.Fl 8
option allows 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.
.It Fl D
The
.Fl D
option sets the TCP_NODELAY socket option which can improve interactive response
at the expense of increased network load.
.It Fl E
The
.Fl E
option stops any character from being recognized as an escape character.
When used with the
.Fl 8
option, this provides a completely transparent connection.
.It Fl K
The
.Fl K
option turns off all Kerberos authentication.
.It Fl L
The
.Fl L
option allows the rlogin session to be run in
.Dq litout
(see
.Xr tty 4 )
mode.
.It Fl d
The
.Fl d
option turns on socket debugging (see
.Xr setsockopt 2 )
on the TCP sockets used for communication with the remote host.
.It Fl e
The
.Fl e
option allows user specification of the escape character, which is
.Dq ~
by default.
This specification may be as a literal character, or as an octal
value in the form \ennn.
.It Fl i
The
.Fl i
option allows the caller to specify a different local name to be used
for authentication.  This option is restricted to processes with uid 0.
.It Fl k
The
.Fl k
option requests rlogin to obtain tickets for the remote host
in realm
.Ar realm
instead of the remote host's realm as determined by
.Xr krb_realmofhost  3  .
.It Fl l
The
.Fl l
option specifies a different
.Ar username
for the remote login.
If this option is not specified, your local username will be used.
.It Fl x
The
.Fl x
option turns on
.Tn DES
encryption for all data passed via the
rlogin session.
This may impact response time and
.Tn CPU
utilization, but provides
increased security.
.El
.Pp
A line of the form
.Dq Aq escape char .
disconnects from the remote host.
Similarly, the line
.Dq Ao escape char Ac Ns ^Z
will suspend the
.Nm
session, and
.Dq Ao escape\ char Ac Ns Ao delayed-suspend\ char Ac
suspends the
send portion of the rlogin, but allows output from the remote system.
By default, the tilde
.Pq Dq ~
character is the escape character, and
normally control-Y
.Pq Dq ^Y
is the delayed-suspend character.
.Pp
All echoing takes place at the remote site, so that (except for delays)
the
.Nm
is transparent.
Flow control via ^S/^Q and flushing of input and output on interrupts
are handled properly.
.Sh KERBEROS AUTHENTICATION
Each user may have a private authorization list in the file
.Pa .klogin
in their home directory.
Each line in this file should contain a Kerberos principal name of the
form
.Ar principal.instance@realm  .
If the originating user is authenticated to one of the principals named
in
.Pa .klogin ,
access is granted to the account.
The principal
.Ar accountname.@localrealm
is granted access if
there is no
.Pa .klogin
file.
Otherwise a login and password will be prompted for on the remote machine
as in
.Xr login  1  .
To avoid certain security problems, the
.Pa .klogin
file must be owned by
the remote user.
.Pp
If Kerberos authentication fails, a warning message is printed and the
standard Berkeley
.Nm
is used instead.
.Sh ENVIRONMENT
The following environment variable is utilized by
.Nm :
.Bl -tag -width TERM
.It Ev TERM
Determines the user's terminal type.
.El
.Sh FILES
.Bl -tag -width /etc/hosts -compact
.It Pa /etc/hosts
.It Pa /etc/hosts.equiv
.It Pa /etc/auth.conf
.It Ev $HOME Ns Pa /.rhosts
.It Ev $HOME Ns Pa /.klogin
.El
.Sh SEE ALSO
.Xr login 1 ,
.Xr rsh 1 ,
.Xr telnet 1 ,
.Xr setsockopt 2 ,
.Xr kerberos 3 ,
.Xr krb_realmofhost 3 ,
.Xr krb_sendauth 3 ,
.Xr ruserok 3 ,
.Xr tty 4 ,
.Xr auth.conf 5 ,
.Xr hosts 5 ,
.Xr hosts.equiv 5 ,
.Xr rlogind 8 ,
.Xr rshd 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .
.Pp
IPv6 support was added by WIDE/KAME project.
.Sh BUGS
The
.Nm
utility will be replaced by
.Xr telnet  1
in the near future.
.Pp
More of the environment should be propagated.