The 10.0 release of the ESRI ArcGIS 10.0 license manager uses FLEXnet v18.104.22.168. If you would prefer to use a newer version of FLEXnet like v22.214.171.124 that comes with Autodesk’s 2011 product line or the even the newest v126.96.36.199 it should work just fine.
Executables involved are lmgrd.exe, lmutil.exe, lmtools.exe as well as any vendor daemon like ARCGIS.EXE.
ArcGIS 10 license manager is not by default bound to FLEXlm port 27004 (so it defaults to 27000) unless that is already taken. You can force the port to be used by editing the service.txt configuration file on the license manager.
Update Autodesk Network License Manager for 2011 release of Autodesk products works also with other vendors.
License usage reports with JTB FlexReport works with ArcGIS 10 as well as the latest v11.9 of FLEXnet/FLEXlm.
Here is a comment by ESRI staff in a newsgroup:
The 10.0 release of the ArcGIS 10.0 license manager uses FLEXnet v188.8.131.52 but has also been significantly reworked to support the more robust ArcGIS 10.0 licensing model which makes use of more secure, encrypted license storage. The license manager will serve licenses to 9.x clients and 10.x clients alike.
As to the result of running the new ArcGIS 10.0 License Manager along side the AutoCad License Manager, your results may vary. With prior license manager releases, it was possible to manipulate the license files to effectively serve ArcGIS licenses from AutoCAD managers, and vice versa provided they were running roughly the same core FlexLM version. With the 10.0 ArcGIS License Manager, this would not be possible as all licenses are stored in an encrypted/secured datastore thus one's ability to "rig" these systems to work together is reduced.
That said, through the 10.0 Beta, there were no reports of "conflicts" between the new ArcGIS License Manager (10.0) and other software vendor's license managers that make use of FlexLM technology. We expect this is in large part due to architectural changes that isolate data stores and eliminate the problems of multiple license managers conflicting by reading the same locations. Regardless, running both these license managers on the same system with the 10.0 License Manager is not recommended. The changes from the ArcGIS License Manger 9.x to 10.x represent an architectural leap; running both the newer ArcGIS License Manager along side another vendor's license manager on the same system may present challenges, and should be thoroughly tested before going into production and risking downing either user base.