Win2k3 VPN using L2TP

I have turned off fragmented packet filtering on my ISA
server to allow IPSec. This seems to have done the
trick. I am now able to login through the VPN.
>-----Original Message-----
>I have configured a VPN on a Win2k3 server. From one
test
>laptop(Win2k) I am able to connect via the internet to
the
>VPN server using L2TP, however from another test laptop
>(also Win2k) I continue to get the message "Error 792:
The
>L2TP connection attempt failed because security
>negotiation timed out" whenever I try to connect (the
>connection dialog never gets further than 'Connecting').
>There are no event log entries on the laptop or server.
>The failed laptop has the same certificates installed as
>the successful laptop as well I've made sure the IPSec
and
>Routing and Remote Access services are running.
>
>Any suggestions would be appreciated.
>.
>