Technical Tip: MultiNet SSH Port Forwarding

In order to use SSH so that remote VMS DECterms will display on a local VMS workstation using a MacOS X machine as the gateway between the two systems, follow these steps:

1. When configuring MultiNet on the customer's VMS system(s), apply all SSH patches and configure the SSH client and server, making sure the SSH server starts up when the system is booted. Note that SSH is not required on your local VMS workstation.

2. Start X11 on the Mac (Titan). It will bring up an 'xterm' window on the Mac screen.

3. Before dialing up the PPP connection, establish an X11 'xterm' window or two on the VMS workstation display, as shown in the following example:

[Titan:~] user1% setenv DISPLAY 200.168.33.49:0.0
[Titan:~] user1% xterm &
[Titan:~] user1% xterm &

The 'setenv DISPLAY' command must specify the IP address on the LAN of the local VMS workstation ("FLASH"), because once PPP is active the Mac won't be able to do DNS lookups for local LAN addresses.

4. Establish the PPP connection.

5. In one of the 'xterm' windows on FLASH, establish an SSH connection to the customer's VMS system:

[Titan:~] user1% ssh -X -C remote-vms-ip

where 'remote-vms-ip' is the IP address of the machine you want to log into using the new PPP link established in Step 3.

5. Once logged into the remote machine, create a DECterm window that will display on the local VMS workstation by virtue of SSH's X11 forwarding:

CUSVMS:: show display

Device: WSA4: [super]
Node: <corporate hostname for this VMS system>
Transport: TCPIP
Server: 10
Screen: 0

CUSVMS:: create/term/detach

7. After a few minutes (depending on line speed, etc.), you should get a DECterm window appearing on your local VMS workstation, logged into the customer's VMS system.

Note: Keystroke performance is highly dependent on the speed of the dialup connection and the customer's internal network load. Make sure you set the DECterm cursor to "non-blinking" for better performance. The one operation that does take a long time is
an X11 "copy to clipboard" function (the Edit->Copy menu in a DECterm window).

You can also configure a print queue on the customer's VMS system that sends jobs to a Laserjet printer in your local office by following Steps 8-10:

8. On the customer's VMS system, configure a queue in DCPS or MultiNet which is tied to port (say) 9101 on "localhost". Anything sent to that queue on the customer's VMS system will be directed to port 9101 on that system.

9. Modify the SSH command used to connect to the customer's machine to forward the remote port to your local printer, for example:

[Titan:~] user1% ssh -X -C -R9101:200.168.33.49:9100 remote-vms-ip

(200.168.13.25 is the IP address of the local Laserjet 5M printer used in this example).

10. When logged into the customer's site, define SYS$PRINT to be the printer you set up in Step 8.

Note: If you have a remote customer that lets you come in via the Internet (e.g., SSH to their site), you can skip Steps 2 and 3 (creating an xterm windows and dialing up to establish a PPP connection), as shown in the following example:

YourVMS:: ssh/remote=(9101:200.168.13.25:9100) remote-vms-IP