I have been experimenting with VPN lately, and I managed to get it running on W7 PC. The problem is, though, that as soon as someone connects to my PC, the internet traffic from their PC is routed through my PC, or so it seems.

Is there a way to leave the VPN (ability to connect to my internal network), while not routing all internet traffic through it?

  • Yes, usually that's an option defined when setting up the VPN (whether to route all traffic through the tunnel or not). Can you post details on what type of VPN you have and it's configuration? – Jim G. Nov 10 '11 at 19:27
  • This depends entirely on what application you are using as a VPN server and how it is configured. The answer to you question as it is currently is "probably". If you want a more detailed answer, you need to provide more details. – MDMarra Nov 10 '11 at 19:31
  • No idea, Windows 7 built in VPN as shown here - youtube.com/watch?v=1s5JxMG06L4 – Coder Nov 10 '11 at 19:37

I assume you're using the "New Incoming Connection..." feature, which enables a PPTP server on the Windows PC.

The problem you're having sounds like a routing issue. The client is routing all traffic through your VPN server, but you only want to route traffic that is destined for your local LAN. Since this configuration is not defined by the PPTP server, this is always a client-side configuration issue.

On your VPN client, you will need to disable "Use default gateway on remote network".

  1. Open Network Connections
  2. Get Properties on the VPN connection you set up
  3. Under the Networking tab, get Properties on IPv4
  4. Click Advanced...
  5. Turn off "Use default gateway on remote network"

What you are looking to setup is called "split tunneling" .. where the VPN client only sends traffic destined for the network on the other end through the tunnel. Some admins don't allow it, because it is thought a vulnerability. If it is enable, there is likely a configuration setting for it on the VPN client. Nic identified how it is controlled on the Microsoft client.

All that being said, you should NOT setup the VPN on a PC that is also sharing it's internet connection. What that effectively does is open the entire internet, through the VPN, to the internal network. I heard nothing about a firewall anywhere ...

If you do want to use the VPN for a "site" rather than just for your PC, you really need to get a firewall and setup the VPN on the firewall. There are a TON of cheap and free ways to do this. I recommended a couple here.

  • Errr… how does a VPN server open up the internal network to the entire Internet? Please explain. – MikeyB Nov 10 '11 at 20:21
  • The box is behind router, and only one password protected user can connect to the VPN, through one open port. Don't see how it's worse than say opening port 80 for WWW. – Coder Nov 10 '11 at 21:01
  • @MikeyB They VPN server doesn't. The VPN tunnel being active and relaying traffic from an unprotected network through the VPN does. – tomjedrz Nov 10 '11 at 23:08
  • @Coder Router not equal firewall, and "someone" implies that there are more than one. In any case, the VPN allows all traffic, not just a single port. For instance, if the PC connecting had malware, the malware could propagate through the VPN to the main network. – tomjedrz Nov 10 '11 at 23:18
  • By the same principle, having any PC on the internal network allows the entire Internet to get to the entire network if the right malware is on it. Unless a client connecting to the VPN is specifically set up to allow it, in general it will be the only machine that gets to talk through the VPN endpoint. – MikeyB Nov 11 '11 at 14:25

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