Edit /etc/hosts so that the first entry looks like

127.0.0.1 localhost home license

This apparently tells IDL to look to the localhost when it looks for the license server.

When you install IDL, the License Wizard will give you the option of pasting in license information. Paste in the license info from perseus.

Modify the "SERVER" line of the license.dat file so it reads like,

SERVER localhost 000blahblahblah 17000

Instead of

SERVER perseus 000blahblahblabh 1700

On a Mac, the license.dat file is stored in like /Applications/itt/license

To start up IDL, set up SSH tunnels to allow your own machine to tunnel in to Perseus to connect to the license manager.

You need to use both of these commands:

ssh -f -N -L 17001:localhost:1700 username@perseus.boulder.swri.edu

ssh -f -N -L 17000:localhost:17000 username@perseus.boulder.swri.edu

I'm not sure whether all of the above steps are necessary but when I did all of them, it worked.

Here's the link to the old RSI Technical tip that explained how to do this. What I have above is a perseus-specific version of what is described in the RSI tip.

[Connecting to a license server through a firewall using an ssh tunnel]

Here's another link that I found less helpful and more complicated, but it provides more explanation about what's going on.

[Setting up an SSH tunnel to get an IDL license from and IDL (flexlm) license server]