I have had this same problem before. We add the WINS servers parameter for the VPN client . Windows always uses WINS server for name resolution of its Primary Domain Controller. If it can not resolve the PDC Netbios name, it will try its cache, DNS. If all fail then it won`t be able to login to the Domain.
We have a Windows 2000 domain running in mixed mode. The client is running XP Pro. When we try to authenticate ,it appears as if it authenticates but we can't get to any of our network resources (such as mapping drives, connecting to printers etc.) We tried it from a Win98 client and the the network log in screen comes back after about a minute or two asking with the log in screen again. We can ping ip addresses on the network. I think we have a setting wrong on the concentrator but I haven't been able to find it.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...