After upgrading a domain from Win NT to Win 2003 all the client computers from the subnets are unable to log on to the domain. The clients on the same network segment as the Domain Controller have no problems. All the communication to/from the other segments passes through the following CISCO routers: 7200vxr and 2600.
TCP-IP is traffic is not affected.
Any idea what protocols and TCP/UDP ports should be allowed for proper communication and authentication?