Reverse SSH Tunnel for ANSYS Licensing

One of our options for ANSYS licensing is the reverse SSH tunnel. This will require a new SSH connection for each job that you start. Here are the pre-requisites and steps to complete the connection for each job. For this process to work, you will need to provide the hostname of your license server with FQDN to before the connection can be established.

First, the prerequisites for the reverse SSH tunnel:

1. You need to be running Ansys FlexLM licenser server locally on your network.
2. Your workstation has normal network access to your local license server.
3. Your workstation has ssh access to a Nimbix instance
4. You have PuTTY installed (Windows)

Here's how you will connect:

1. Launch PuTTY
2. Click on connection -> SSH -> Tunnels in the left side bar.
3. Tick "Remote" for destination
4. Tick "Local ports accept connections from other hosts" 
5. Add the source port and destination. The source ports for ANSYS would be 1055, 2325, 2326 and destination would be the hostname of your license server. In the screen shot below I've added port 1055 and 2325, and I also show how the entry will look for 2326. (Your "Destination" hostname with FQDN will obviously differ from the one in the below screenshot.)

6. Save this in a profile so it will save and you don't have to set this up each time. Do this by clicking on "Session" at the top of the left side bar, create a name under "Saved Sessions" and click "Save". Now when you launch PuTTY, you'll be able to load this session without having to load ports/destination each time. 


The rest will be set up on our side which will allow you to connect.

So for every job you launch, this is the process:

1. Launch your job
2. Get the FQDN for job instance. Do this by clicking on the "i" button on your dashboard (next to the 'Shutdown' button) on the job that you want to connect to. In the window that pops up, scroll down until you see the Secure Shell connection method. 

3. Launch PuTTY and copy the "Address" shown above into the the "Host Name" field inside PuTTY. Click "Open" and when prompted, copy and paste the password as well.

4. SSH to job instance using PuTTY
5. As soon as ssh connection establishes Ansys should launch inside the job instance you created.

There is a timeout of 5 minutes, so you'll need to SSH within 5 minutes of launching your job.

If you have any issues along the way, reach out to and we can help you work through it.


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