Autodesk licensing uses the ports 2080 and 27000-27009, so check that your firewall does not block these ports. Check the firewalls both on the workstations and on the license server.
If 2080 is blocked, you’ll see this error in the FLEXLM_DIAGNOSTICS output:
FLEXnet Licensing error:-15,570. System Error: 10035 “WinSock: Operation would block”
A network license (.lic) file includes this line
VENDOR adskflex port=2080
which suggests [to me] that you can change the port number.
So I changed the port number in the .lic, saved the file, and restarted the license server.
But adskflex still used 2080:
8:33:58 (lmgrd) License file(s): C:\Program Files\Autodesk Network License Manager\SFTIMA2010.lic
8:33:58 (lmgrd) lmgrd tcp-port 27000
8:33:58 (lmgrd) Starting vendor daemons ...
8:33:58 (lmgrd) Starting vendor daemon at port 2080
8:33:58 (lmgrd) Using vendor daemon port 2080 specified in license file
That last log entry “Using vendor daemon port 2080 specified in license file” makes it look like I didn’t save my changes, but I know I did. My license file says 2082, not 2080.
After a little research, I found this KB article, which explains that the port 2080 is officially registered to Autodesk through the IANA, and you should “reassign the port in the conflicting application, or unblock the port”.
If for some reason you must use a different port, delete the “port=2080″ from your license file. The adskflex vendor daemon will automatically find an available TPC/IP port.