1

Setup:

  • 1 PC with Windows XP SP2
  • 1 network card connected to a LAN which provides internet access (LAN_CONN)
  • 1 network card connected to a VPN link set up by the provider (VPN_CONN)
  • VPN_CONN is set up as a LAN connection, not as a VPN one (the provider gave me an ip and a gateway to connect to).

Problem:

VPN_CONN works fine when connected but I lose access to the internet provided by LAN_CONN.

I have searched for solutions regarding this problem but none of them helped me solve it. Everything I found assumes that VPN_CONN is set up as a VPN connection. Can someone help me solve it? Thank you in advance.

I may have been a bit unclear in defining the problem but i'll try to provide more information if needed.

1
  • Do you do anything special to the PC beyond standard configurion (IP, mask, Gateway) the VPN NIC? Do you install VPN software, or setup the VPN NIC in an atypical manner?
    – tomjedrz
    Dec 14, 2009 at 17:10

3 Answers 3

4

On the properties of your VPN connection, click on TCP/IP and then in properties again. Search for an advanced button. There is a checkbox that says something like: Use this as default gateway. Or maybe something related to gateway. I don't know exactly the option because I'm in front of a linux now. After find and unmark this checkbox, click ok on every window and then connect to your VPN. This should work.

Ps.: This configuration is done on the client side.

3

I have similar setup, where 1st network card is for intranet only (10.0.x.x) and 2nd one for internet. After installing 2nd card I faced the problems when Windows was routing all the internet traffic trough 1st network card, but the intranet has very limited internet connection.

Solution:

This batch file being executed during startup:

route DELETE 10.0.0.0
route DELETE 0.0.0.0
route ADD 10.0.0.0 MASK 255.0.0.0 10.0.0.1
route ADD 0.0.0.0 MASK 0.0.0.0 192.168.1.1

Where 10.0.0.1 is the gateway for intranet, and 192.168.1.1 for internet.

Notes:

If this is not your case, I recommend you analyzing your routing mechanism by issuing following command:

route print

Or, trace your traffic by some handy tool like wireshark.

2

The issue is that when you're connecting to your VPN the routing table on your PC is updating to use the VPN as a default gateway for everything.

What you're trying to do is called "split tunnel access" and it would require adding a route to your LAN default gateway that overrides the VPN gateway.

The cable guy at microsoft has an article on ways of setting this up:

http://technet.microsoft.com/en-us/library/bb878117.aspx

It should also be noted that depending on the VPN solution in use you may be disconnected as soon as your routing table changes.

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