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REXECD (Remote EXEcution Command Daemon) is a server that allows execution of the REXEC or RSH (Remote Shell Protocol) command from a remote host over the TCP/IP network. The client function is performed by the REXEC process.
REXEC command is used to define user ID, password,
host address, and the process to be started on the remote host. Both server and
client are linked over the TCP/IP network.
Figure: REXECD Principle
The REXECD service machine supports both the remote execution protocol (REXEC) on port 512, and the remote shell protocol (RSH) on port 514.
Both client and server functions are implemented under VM.
The REXECD machine can transfer commands to a user machine, or slave machine. A slave machine is useful for the user who does not have his own virtual machine defined in the VM system where he wants to execute some process.
Slave machines are autologged when REXECD executes its PROFILE EXEC. The following is an example of the REXECD parameters. This is part of the PROFILE EXEC. This file can be shared between the REXECD virtual machine and the slave machine(s).
..... 'REXECD -d -r -s VMUSER14 PASSW1 -s SLAV2 PSW2'
Where:
When using the REXECD VM server from another host, you are prompted for a user ID and a password. You can either enter a valid user ID and its RACF password (if the RACF option is enabled) or the keyword guest and a null password to use one of the slave machines. To enable the RACF option (that is to use the RACF password to autolog a user ID) the following steps must be performed:
When using the client function from VM (REXEC command) the NETRC DATA file may provide you with an alternative to specifying the user ID and password as REXEC parameters. This file should be stored using the A0 filemode.
Example of NETRC DATA A0 file:
machine fsc5 login guest password xxx machine psfred login FRED password pass
The first entry identifies a slave machine (the password does not matter).
The following is a sample response that is displayed as a result of using
the REXEC command and the NETRC DATA file:
TCP/IP for MVS includes both server and client remote execution functions
(REXEC). The implementation is as follows:
The remote execution protocols allow your TSO users to execute commands on
remote TCP/IP hosts and receive the results on their TSO terminal.
See REXEC above.
The remote execution command daemon (REXECD) is the server that allows
execution of a TSO batch command that has been received from a remote TCP/IP
host. This server supports both the remote execution protocol (REXEC) and the
remote shell protocol (RSH).
Note: The RSH protocols are supported for the REXEC functions only.
Remote login (RLOGIN) is not supported. If the MVS system runs OpenEdition, an
RLOGIN server is supplied with OpenEdition MVS.
See REXECD above.
Another possibility to submit jobs to an MVS/JES subsystem is the job
submission facility from an MVS FTP server (see
MVS for more information).
The rexecd daemon is a subserver controlled by the inetd subsystem (also
known as the super daemon).
The $HOME/.netrc file can be used to specify automatic login information for
the user ID and password to use at the foreign host. Since this file is not
encrypted, the automatic login feature is not available when your AIX system
has been configured with the securetcpip command.
The rsh command and the rshd server (daemon) can be
used. Since rsh and rshd do not provide a secure environment for transferring
files, they are disabled by running the securetcpip command.
The securetcpip command is used to enable additional TCP/IP security
environment by disabling commands that are not trusted.
For more information about the securetcpip command,
please refer to AIX Version 3.2 for RISC System/6000 Communication Concepts
and Procedures.
TCP/IP for OS/2 provides client and server functions of REXEC. Before
activating the REXEC server, the variables USERID and PASSWORD
have to be defined. They are used to define which remote users can access your
system. REXECD and REXEC are the commands used for server and client
respectively. The REXEC command uses the /ETC/NETRC file to automate the login
process.
OS/2 provides client and server (RSHD) functions of RSH. Before activating
the RSH server, the RHOSTS file in the ETC directory must be created. It is
used by the RSH server to verify the authorization of remote hosts. You must
specify the full domain name (for example, joe.watson.ibm.com) of the
remote hosts.
The following is an example REXEC session from OS/2 to AIX V3.
TCP/IP for DOS is implemented with the client REXEC and the RSH commands.
REXEC requires an REXEC Daemon to be running on the foreign host. This REXEC
command is used to provide the necessary parameters, user name, password,
internet address, and command to be executed on the foreign host. RSH requires
a RSH server to be running on the foreign host. Like REXEC, the RSH command
executes a command on the remote host. However, RSH neither requires nor allows
you to supply a password.
rexec fsc5 q t
TIME IS 05:43:10 EUR FRIDAY 02/10/95
CONNECT= 00:01:58 VIRTCPU= 000:02.41 TOTCPU= 000:04.59
Ready; T=0.39/0.71 05:43:14
4.8.2.2 MVS
4.8.2.3 AIX
All AIX systems are implemented with both REXEC client and server.
4.8.2.4 AIX/6000
4.8.2.5 OS/2
[C:\]rexec rs60002 -l paul -p mypasswd ls -ls
total 368
4 drwxr-xr-x 2 li staff 512 Sep 09 18:49 hippi
4 drwxr-xr-x 3 li staff 512 Sep 09 11:07 info
84 -rw-r--r-- 1 li staff 83913 Sep 18 11:51 krypto.ps.Z
4 drwxr-xr-x 4 li staff 512 Sep 17 11:10 mit
4 -rw-r--r-- 1 li staff 1818 Sep 17 11:14 x11r5doc.du
4.8.2.6 DOS
X
Window System