Windows VPN when client is same subnet as server

[Tim Kowal]

I am a network consultant, and I often come across customers who want VPN,
but their network is on a common subnet like 192.168.0.0. We run into the
problem where the home PCs are on the same subnet, and of course the VPN
won't work. I was trying to think of a clever way around this, and wondered
if someone would tell me if this would work (or what else is possible):

Let's say the server is 192.168.0.1, and this is the same SN as the client.
If I could make get the VPN server to serve IP addresses of a more unique
scope like 192.168.88.x, could I change the Subnet mask of the server to
255.255.0.0 and thereby allow the server to still communicate to the
clients?

Am curious if this would work!

Tim

 

[BobC]

I am a network consultant, and I often come across customers who want VPN,
but their network is on a common subnet like 192.168.0.0. We run into the
problem where the home PCs are on the same subnet, and of course the VPN
won't work.

It will with the correct equipment. Get a router that is also a
point-to-point vpn device. Netgear and others make these. The router is
smart enough if, configured correctly, to allow the same LAN addressing at
both ends of the VPN.

Go to Netgear's site and read the manual for a VPN router.

I was trying to think of a clever way around this

The router manufaturers have figured this out.

 

[che-guevara]

Forgive me if I don't sound too sure about an answer because I
just worked out a lot of the vpn stuff myself and am still new to
the practicalities, but I believe that if you connect to the server
with the client set to adopt a dynamic ip address - the server shoul
give the connecting machines a unique ip.
you have to have a server which allocates dhcp (or a firewall which i
vpn capable and allocates dhcp itself).

With my limited knowledge of the subject i would say play about
with DHCP - or just allocate a new address range to your connectin
network


-
che-guevar

 

[Lanwench [MVP - Exchange]]

It will with the correct equipment. Get a router that is also a
point-to-point vpn device. Netgear and others make these. The router is
smart enough if, configured correctly, to allow the same LAN addressing at
both ends of the VPN.

Go to Netgear's site and read the manual for a VPN router.

I agree with the idea that a hardware appliance as endpoint is a good idea,
but I have never seen one (even with the more expensive variety) that will
allow VPN to work if the subnets are the same.
I tell people who want VPN to change their home networking schemes - this is
rarely difficult.