I believe the ArcGIS license manager and the AutoDesk license manager both want to default to Port 27000. I dealt with a similar issue when I was still in our Engineering Division in Public Works. We chose to move the ESRI license manager port number over to 27001. If you installed the 64bit license managers to the C drive of your server/workstation, cruise over to c:\program files\arcgis\bin. In the "bin" folder, you'll find the service.txt file. Make a backup of it before moving forward. Open service.txt in notepad and you'll see the first line should read:
SERVER this_host ANY 27000
edit that line to read..
SERVER this_host ANY 27001
One caveat, if your License Manager is running on a virtual machine (e.g. VMWare) like ours is, then the above portion that says "ANY" should be the "VM_UUID=****" as specified in License Server Administrator > Authorization screen > Machine IDs screen > Cloud Instance ID line.
Save and close the newly edited service.txt file and then go over to ESRI License Server Administrator app and reread your license file. This will shift the ESRI license manager over to Port 27001. Hopefully, this will eliminate overlapping Port use by the two FlexNet installations
I found it was much easier to move the port for the ESRI License Manager than to make changes to our AutoDesk license management environment. Our Engineering Division contracted out the deployment and maintenance of the AutoDesk license management to our local AutoDesk Reseller so I wasn't interested in messing with their work. I did coordinate my effort with our AutoDesk Reseller.
