The Windows VPN client, when using the "logon using dial-up networking" feature, is designed to work in the situation where your VPN logon and your domain user logon are the same. IOW, it is designed to work with a Windows RRAS server, not a router. Since you didn't specify in your OP, and I didn't ask, I assumed this was what you were doing. If the VPN connection is through your router and not a Windows RRAS server, I don't think you will be able to use the logon using dial-up networking feature successfully.