I had following problem. Cisco 2651 acts as LNS server for L2TP connections, LAC is WinXP. Network topology:
fa/0.901 has address 10.1.1.1 adn fa0/0.900 has address 10.0.0.254 . When clients from subnet 10.1.1.1/24 connect to 10.1.1.1 , everything works perfect - IPSec protected L2TP tunnel comes up. The same happens when clients from subnet 10.0.0.0/24 connect to 10.0.0.254 . But when client tries to connect to address from different network (10.1.1.0/24 to 10.0.0.254 and 10.0.0.0/24 to 10.1.1.1), it does not work.
Debug output and Cisco config are attached.
I found nothing similar to my problem on Internet. Is this a bug or I missed something?