Brief version: A 12.4 system cannot use an accept-dialout vpdn on a
12.2 system for modem access. See previous postings for details.I constructed an L2TP filter to run on an intermediate host. It waits for the OCRQ packet from the 12.4 system and removes the Cisco-specific AVP 102 (Username). Everything else it forwards to the 12.2 system. This makes the connection work fine, so the (extraneous, null) Username AVP is indeed the problem.
I then made my filter change the Username AVP to some unrecognized Cisco-specific attribute. This was also handled correctly the 12.2 system and the connection worked.
Finally, I made my filter leave the AVP 102 in the packet but make the value non-null (I made it "x"). Again this made the 12.2 system happy.
Does anyone know how to convince 12.4 to omit the AVP 102 or make it non-null?
Dan Lanciani ddl@danlan.*com