RLM 9.0 and above, supports the option to specify the ISV port

When running ./rlm use the -c option to specify all the licenses you want to serve. Each should have its own port in the ISV vendor line.

For ie:

Running ./rlm -c solidAngle.lic -c foundry.lic -c peregrine.lic -c joeAlter.lic  Notice the

If the ISV port is not specified, the rlm server will assign a random port to each license. This is ok for only some vendors like SolidAngle. But The Foundry products, Peregrine Labs, and Joe Alter (as in the example) will need a specific port.
After assigning the port in the license files, you can edit your maya.env to tell the plugins the vendor port

When opening a The Foundry product, select the RLM server, and write the license location as 35099@licenseServerName

Your ./rlm command should yield something like this: