RSH(1)							    BSD General Commands Manual 						    RSH(1)

NAME

     rsh -- remote shell

SYNOPSIS

     rsh [-45FGKdefnuxz] [-U string] [-p port] [-l username] [-P N|O] host [command]

DESCRIPTION

     rsh authenticates to the rshd(8) daemon on the remote host, and then executes the specified command.

     rsh copies its standard input to the remote command, and the standard output and error of the remote command to its own.

     Valid options are:

     -4, --krb4
	     The -4 option requests Kerberos 4 authentication. Normally all supported authentication mechanisms will be tried, but in some cases
	     more explicit control is desired.

     -5, --krb5
	     The -5 option requests Kerberos 5 authentication. This is analogous to the -4 option.

     -K, --broken
	     The -K option turns off all Kerberos authentication. The security in this mode relies on reserved ports. The long name is an indica-
	     tion of how good this is.

     -n, --no-input
	     The -n option directs the input from the /dev/null device (see the BUGS section of this manual page).

     -d      Enable setsockopt(2) socket debugging.

     -e, --no-stderr
	     Don't use a separate socket for the stderr stream. This can be necessary if rsh-ing through a NAT bridge.

     -x, --encrypt
	     The -x option enables encryption for all data exchange. This is only valid for Kerberos authenticated connections (see the BUGS sec-
	     tion for limitations).

     -z      The opposite of -x.  This is the default, and is mainly useful if encryption has been enabled by default, for instance in the
	     appdefaults section of /etc/krb5.conf when using Kerberos 5.

     -f, --forward
	     Forward Kerberos 5 credentials to the remote host.  Also settable via appdefaults (see krb5.conf).

     -F, --forwardable
	     Make the forwarded credentials re-forwardable.  Also settable via appdefaults (see krb5.conf).

     -l string, --user=string
	     By default the remote username is the same as the local. The -l option or the username@host format allow the remote name to be speci-
	     fied.

     -n, --no-input
	     Direct input from /dev/null (see the BUGS section).

     -p number-or-service, --port=number-or-service
	     Connect to this port instead of the default (which is 514 when using old port based authentication, 544 for Kerberos 5 and non-
	     encrypted Kerberos 4, and 545 for encrytpted Kerberos 4; subject of course to the contents of /etc/services).

     -P N|O|1|2, --protocol=N|O|1|2
	     Specifies the protocol version to use with Kerberos 5.  N and 2 select protocol version 2, while O and 1 select version 1. Version 2
	     is believed to be more secure, and is the default. Unless asked for a specific version, rsh will try both.  This behaviour may change
	     in the future.

     -u, --unique
	     Make sure the remote credentials cache is unique, that is, don't reuse any existing cache. Mutually exclusive to -U.

     -U string, --tkfile=string
	     Name of the remote credentials cache. Mutually exclusive to -u.

     -x, --encrypt
	     The -x option enables encryption for all data exchange. This is only valid for Kerberos authenticated connections (see the BUGS sec-
	     tion for limitations).

     -z      The opposite of -x.  This is the default, but encryption can be enabled when using Kerberos 5, by setting the libdefaults/encrypt
	     option in krb5.conf(5).

EXAMPLES

     Care should be taken when issuing commands containing shell meta characters. Without quoting, these will be expanded on the local machine.

     The following command:

	   rsh otherhost cat remotefile > localfile

     will write the contents of the remote remotefile to the local localfile, but:

	   rsh otherhost 'cat remotefile > remotefile2'

     will write it to the remote remotefile2.

FILES

     /etc/hosts

SEE ALSO

     ktelnet(1), krb_realmofhost(3), krb_sendauth(3), hosts.equiv(5), krb5.conf(5), rhosts(5), kerberos(8) rshd(8)

HISTORY

     The rsh command appeared in 4.2BSD.

AUTHORS

     This implementation of rsh was written as part of the Heimdal Kerberos 5 implementation.

BUGS

     Some shells (notably csh(1)) will cause rsh to block if run in the background, unless the standard input is directed away from the terminal.
     This is what the -n option is for.

     The -x options enables encryption for the session, but for both Kerberos 4 and 5 the actual command is sent unencrypted, so you should not
     send any secret information in the command line (which is probably a bad idea anyway, since the command line can usually be read with tools
     like ps(1)).  Forthermore in Kerberos 4 the command is not even integrity protected, so anyone with the right tools can modify the command.

HEIMDAL 
							 February 20, 2004							   HEIMDAL