Windows 2003 Cluster Shares (DFS) & NT4

this is a wierd one :

NT4 client CAN connect while on the LAN to a WIN2K3 box’s DFS and normal shares but not when dialled in, or broadband.

The client CAN connect to WIN2K3 shares on another server from both the LAN and dialup.

XP clients can connect to everything from everywhere!

Not sure why the 2003 cluster doesn’t like the NT4 client when outside the firewall and yet can connect to other 2k3 shares but not on this particular cluster. I am trying to test connection to another cluster but finding this problem strange.

Great if anyone has any ideas.
Cheers.

ps. there are no ports blocked on the firewall and using SecureRemote. don’t think this is the issue though as other clients can connect and also NT4 clients connect to everywhere else apart from this cluster. the cluster is fine from the LAN….so far…