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In my office, we are working off one IP address currently, and this lets us connect a single computer to one of our client's VPNs, which effectively locks out multiple people from working with that client (1 VPN connection per IP). Is there a particular way via some software or service that will allow us to 'fake' an outgoing IP so we can make multiple connections? We are using Windows 7, if that helps. I've heard of systems like Tor, but I'm not really sure how that can be applied to my situation. Thanks!

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This question is tip-toeing on circumventing IT Policy; and since we're usually the policy enforcers... It's not possible to ask the VPN endpoint to increase the limit? – Chris S Apr 7 '11 at 0:09
This sort of thing is usually solved by a site-to-site (LAN-to-LAN) IPSec tunnel. – gravyface Apr 7 '11 at 2:20
It would be good to know what kind of VPN it is. What's the client you connect with? – nedm Apr 7 '11 at 23:59
Chris - I know it is circumventing IT policy, however it is approved by both my company and our client, so it isn't an issue in this case – Evan Apr 12 '11 at 0:11
up vote 3 down vote accepted

One thing you can try is, establish the VPN connection at the router level, and it should handle all the connections for you.

If you are using a cheap router that doesn't allow VPN connections (not VPN passthrough), another potential cheap/free solution would be to update your router's firmware if possible to unlock features it may be capable of. <-- Check if your router is compatible

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You can then set up routes to ensure that traffic only for the VPN goes through the VPN tunnel, all other traffic destined to leave your local lan will pass out through the router normally. – Matt Apr 8 '11 at 0:58
It's also possible to buy a cheap router that supports alternative firmware like DDWRT, configure it to run the VPN tunnel and place this behind your existing router. Set up a router on the existing router to point to the VPN router for the network range of the foreign network. – Matt Apr 8 '11 at 0:59

I agree (depending on the type of VPN you have to work with) that you should look for a site-to-site solution. However, rather than trying to unlock a feature that may exist in your router, it may be easier to set up a port-forwarding rule on the router/FW to pass the ports the VPN runs over to an internal VPN "client" on the DMZ or LAN interface that then shares the connection with the rest of the LAN.

EDIT: @Zypher correctly points out that you may need to enable passthrough rather than port-forwarding depending on what type of VPN you're using. For that matter, if it's an SSL VPN and you're running the client, you may not need either -- a regular statefull NAT'd firewall may not interfere at all with the connection. Again, it depends on the type of VPN your client has.

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IPSec is actually an IP Protocol (Type 50) and can't be forwarded, since it's not a standard TCP stream – Zypher Apr 8 '11 at 0:19
True -- that's why the "depending on the type..." disclaimer & my comment/question above. I'm guessing it's either PPTP or IPSec since OP only mentions Windows 7, and yeah, if it's IPSec one would need to enable IPSec passthrough if it's available on the router rather than port-forwarding. Technically, PPTP requires passthrough for GRE as well, but may actually work with either port-forwarding or passthrough depending on the equipment. If it's something else like SSL/OpenVPN, then port-forwarding will do the job. – nedm Apr 8 '11 at 0:53

This is the limiatation of PPTP Passthrough. Sourssprite solution will work. However some people will not have a router that can terminate the VPN tunnel. What you are actually describing is VPN passthrough where the router allows outbound VPN connections. There are problems though and I know I found an article called Multiple VPN Connections – Why It Isn’t Possible which explains why this happens and ways around it. It's a good read!

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