HP-UX Reference (11i v2 03/08) - 1M System Administration Commands N-Z (vol 4)

r
remshd(1M) remshd(1M)
NAME
remshd - remote shell server
SYNOPSIS
/usr/lbin/remshd
[-lmns]
In Kerberos V5 Network Authentication Environments
/usr/lbin/remshd
[-clmnKkRr]
DESCRIPTION
The
remshd command is the server for the
rcp, rdist and remsh commands, rcmd() and the
rcmd_af() function in case of IPv6 systems (see rcp(1), rdist(1), remsh(1), rcmd(3N)), and
rcmd_af(3N).
remshd allows two kinds of authentication methods:
1. Authentication based on privileged port numbers where the client’s source port must be in the
range 512 through 1023. In this case
remshd
assumes it is operating in normal or non-
secure environment.
2. Authentication based on Kerberos V5. In this case
remshd
assumes that it is operating in a
Kerberos V5 Network Authentication, i.e., secure environment.
The inetd daemon invokes
remshd if a service request is received at ports indicated by shell or
kshell services specified in /etc/services
(see inetd(1M) and services(4)). Service requests arriv-
ing at the
kshell port assume a secure environment and expect Kerberos authentication to take place.
To start
remshd from the inetd daemon in a non-secure environment, the configuration file
/etc/inetd.conf must contain an entry as follows:
shell stream tcp nowait root /usr/lbin/remshd remshd
In a secure environment, /etc/inetd.conf
must contain an entry:
kshell stream tcp nowait root /usr/lbin/remshd remshd -K
The above configuration line will start remshd in IPv4 mode. To run remshd
in IPv6 mode, the fol-
lowing line must be present in the
/etc/inetd.conf
file:
shell stream tcp6 nowait root /usr/lbin/remshd remshd
Note: For IPv6 applications, the protocol
tcp has to be changed to tcp6. See the inetd.conf (4)
manpage for more information.
To prevent non-secure access, the entry for
shell should be commented out in /etc/inetd.conf
.
Any non-Kerberos access will be denied since the entry for the port indicated by
shell has now been
removed or commented out. In such a situation, a generic error message,
rcmd: connect hostname : Connection refused
is displayed. See DIAGNOSTICS for more details.
Note: By commenting out the entry for the port, access by other clients such as
rdist will also be
prevented.
Options
remshd recognizes the following options.
-l This option can be used to forbid authentication based on the user’s .rhosts file unless the
user is a superuser.
-n This option can be used to disable transport-level keep-alive messages. Otherwise, the mes-
sages are enabled. The keep-alive messages allow sessions to be timed out if the client crashes
or becomes unreachable.
-m With this option enabled, remshd returns immediately after its child process gets killed; it
does not wait for all its sub child processes to die. This in turn makes remsh not to wait even
when the sub child processes are running remotely. As a result, remsh will not appear hung.
It is recommended that users do not use -m option, if they want remshd to wait until the com-
pletion of all the sub child processes. Otherwise, the user may not get an expected result. This
option is applicable only to remsh with a secondary socket connection.
Section 1M−−662 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: August 2003