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Neither the name of the Institute nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $Id$ .\" .Dd February 20, 2004 .Dt RSH 1 .Os HEIMDAL .Sh NAME .Nm rsh .Nd remote shell .Sh SYNOPSIS .Nm .Op Fl 45FGKdefnuxz .Op Fl U Pa string .Op Fl p Ar port .Op Fl l Ar username .Op Fl P Ar N|O .Ar host [command] .Sh DESCRIPTION .Nm authenticates to the .Xr rshd 8 daemon on the remote .Ar host , and then executes the specified .Ar command . .Pp .Nm copies its standard input to the remote command, and the standard output and error of the remote command to its own. .Pp Valid options are: .Bl -tag -width Ds .It Xo .Fl 4 , .Fl Fl krb4 .Xc The .Fl 4 option requests Kerberos 4 authentication. Normally all supported authentication mechanisms will be tried, but in some cases more explicit control is desired. .It Xo .Fl 5 , .Fl Fl krb5 .Xc The .Fl 5 option requests Kerberos 5 authentication. This is analogous to the .Fl 4 option. .It Xo .Fl K , .Fl Fl broken .Xc The .Fl K option turns off all Kerberos authentication. The security in this mode relies on reserved ports. The long name is an indication of how good this is. .It Xo .Fl n , .Fl Fl no-input .Xc The .Fl n option directs the input from the .Pa /dev/null device (see the .Sx BUGS section of this manual page). .It Fl d Enable .Xr setsockopt 2 socket debugging. .It Xo .Fl e , .Fl Fl no-stderr .Xc Don't use a separate socket for the stderr stream. This can be necessary if rsh-ing through a NAT bridge. .It Xo .Fl x , .Fl Fl encrypt .Xc The .Fl x option enables encryption for all data exchange. This is only valid for Kerberos authenticated connections (see the .Sx BUGS section for limitations). .It Xo .Fl z .Xc The opposite of .Fl x . This is the default, and is mainly useful if encryption has been enabled by default, for instance in the .Li appdefaults section of .Pa /etc/krb5.conf when using Kerberos 5. .It Xo .Fl f , .Fl Fl forward .Xc Forward Kerberos 5 credentials to the remote host. Also settable via .Li appdefaults (see .Xr krb5.conf ) . .It Xo .Fl F , .Fl Fl forwardable .Xc Make the forwarded credentials re-forwardable. Also settable via .Li appdefaults (see .Xr krb5.conf ) . .It Xo .Fl l Ar string , .Fl Fl user= Ns Ar string .Xc By default the remote username is the same as the local. The .Fl l option or the .Pa username@host format allow the remote name to be specified. .It Xo .Fl n , .Fl Fl no-input .Xc Direct input from .Pa /dev/null (see the .Sx BUGS section). .It Xo .Fl p Ar number-or-service , .Fl Fl port= Ns Ar number-or-service .Xc 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 .Pa /etc/services ) . .It Xo .Fl P Ar N|O|1|2 , .Fl Fl protocol= Ns Ar N|O|1|2 .Xc Specifies the protocol version to use with Kerberos 5. .Ar N and .Ar 2 select protocol version 2, while .Ar O and .Ar 1 select version 1. Version 2 is believed to be more secure, and is the default. Unless asked for a specific version, .Nm will try both. This behaviour may change in the future. .It Xo .Fl u , .Fl Fl unique .Xc Make sure the remote credentials cache is unique, that is, don't reuse any existing cache. Mutually exclusive to .Fl U . .It Xo .Fl U Pa string , .Fl Fl tkfile= Ns Pa string .Xc Name of the remote credentials cache. Mutually exclusive to .Fl u . .It Xo .Fl x , .Fl Fl encrypt .Xc The .Fl x option enables encryption for all data exchange. This is only valid for Kerberos authenticated connections (see the .Sx BUGS section for limitations). .It Fl z The opposite of .Fl x . This is the default, but encryption can be enabled when using Kerberos 5, by setting the .Li libdefaults/encrypt option in .Xr krb5.conf 5 . .El .\".Pp .\"Without a .\".Ar command .\".Nm .\"will just exec .\".Xr rlogin 1 .\"with the same arguments. .Sh EXAMPLES Care should be taken when issuing commands containing shell meta characters. Without quoting, these will be expanded on the local machine. .Pp The following command: .Pp .Dl rsh otherhost cat remotefile \*[Gt] localfile .Pp will write the contents of the remote .Pa remotefile to the local .Pa localfile , but: .Pp .Dl rsh otherhost 'cat remotefile \*[Gt] remotefile2' .Pp will write it to the remote .Pa remotefile2 . .\".Sh ENVIRONMENT .Sh FILES .Bl -tag -width /etc/hosts -compact .It Pa /etc/hosts .El .\".Sh DIAGNOSTICS .Sh SEE ALSO .Xr rlogin 1 , .Xr krb_realmofhost 3 , .Xr krb_sendauth 3 , .Xr hosts.equiv 5 , .Xr krb5.conf 5 , .Xr rhosts 5 , .Xr kerberos 8 .Xr rshd 8 .\".Sh STANDARDS .Sh HISTORY The .Nm command appeared in .Bx 4.2 . .Sh AUTHORS This implementation of .Nm was written as part of the Heimdal Kerberos 5 implementation. .Sh BUGS Some shells (notably .Xr csh 1 ) will cause .Nm to block if run in the background, unless the standard input is directed away from the terminal. This is what the .Fl n option is for. .Pp The .Fl 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 .Xr ps 1 ) . Forthermore in Kerberos 4 the command is not even integrity protected, so anyone with the right tools can modify the command.