VPN Networking

What can cause a remote connection that works over the
top of the user's internet connection to be successful
when the user accesses the internet via dialup, and fail
when connecting via cable, DSL, or satellite?



Windows Server 2003 AD (freshly upgraded from NT 4.0)
Firewall is Sonicwall Pro 300
VPN software is the Sonicwall Pro (SafeNet 8.0)

Before the upgrade all laptop users were fine, same
client configurations, same security policy (sonicwall
security policy).
Now, its about half and half... users that have no
issues, and users that cannot access the network via the
vpn. The error is that it cannot find a DC to
authenticate.

** If a user that can't authenticate logs on a different
machine, all is well.
** If a user that has no issue logs on a machine that a
user had issues with, all is well.
** If a user that has issues dials up to the internet on
the very same machine that can't find a DC when connected
via broadband... all is well.

It seems to point to the client machine and the specific
users profile...
Any help, thoughts, advice, greatly appreciated...


KKohl