VPN Connection drops unexpectedly

VPN Connection drops unexpectedly

Post by khnp9 » Wed, 24 Dec 2003 04:23:45

I have two users whose VPN connection to my firewall gets dropped
after been connected for 5 to 10 minutes and whenever a large amount
of throughtput is put through the vpn connection. Lately, I noticed
that it happens wether there is activity or not in the connection.

The users are using Windows 2000 professional (SP4) and winxp pro over
DSL connections.

The vpn is initiated by the user to our Watchguard 1500 firebox. Once
the firebox authenticates the user and the user starts synchronizing
data, the VPN drops and no indication is given in the user side that
the connection dropped.

We have been using VPN for years and from a large variety of systems
with different operating systems including those that these two users
have installed. Also, our users use dial-up, t1, cable modem and dsl
to connect. Up to about a month ago, I had never experienced any
problems with the vpn connection other than normal user mistakes. THe
only diferences are a move from a WinNT 4.0 SP6 domain/pdc to a
win2003 with active directory domain/pdc server. This issue is
absolutely crazy. The two users with the problem are new users to the
vpn and the old users are not experiencing any difficulties

Watchguard information on the subject is to say the least non

Have anybody seen this problem before.

THanks for the help you may provide.

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At my company we have some stupid VPN that when connected, you are disallowed
from changing the network routing tables or enabling/disabling network
adapters. They do this to prevent someone from bridging the WAN to the
Internet, which is good, but but its annoying all the same. At least it was
"just annoying" in the past.

Well guess what, the new AS4 scheme of using this RNDIS network adapter
basically means I cannot connect to the VPN to retrieve my Exchange server
data, and then sync that data to my PDA. The instant I connect or disconnect
the USB cable, VPN drops. I tried to connect PDA first, then dialup the VPN
but then what happens is that the activesync connection disconnects when the
VPN starts.

Can anyone think of a workaround? I tried the stuff mentioned in the AS4
troubleshooting guide where it talks about VPNs but this is not applicable to
mine because there is not an extra...whatever to uncheck in the RNDIS driver.
I can uncheck MS client or TCP/IP but that breaks sync. The VPN has its
own virtual network adapter, it does not seem to work the same way as what
the MS article is referring to.

I don't know what kind of VPN we have, it seems to be a blend of PPTP and
some custom stuff.

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