VPN IP Addressing Question

[Soopafresh]

Forgive me for my ignorance on this issue, but I'm wondering how to get a VPN connection working if both sides are using the same 3rd octet in the IP addressing scheme. See diagram below. I'm guessing the routing tables get confused (ie, is the request being made to a device on the local network or on the remote one?)

[gadgetguy]

It's been a while since I did VPN, but I'm pretty sure they have to be separate subnets. So I think the only way you can have the same 3rd octet is to change the subnet mask.

[stiltman]

Depending on your equipment, placing the vpn appliance into bridge mode will acomplish what you want.


Edit, that wont work
Thinking about it, you have to have a different subnet somewhere in the mix. Whether it be your computer or the VPN appliance you're connecting to. That's why you need VPN

However take for instance
my computer's home network is 172.1.1.X
My work's network is 172.1.1.X

I can still use VPN because my public IP is actually different, or my work's public IP is actually different. However once connected, they are the same

[CogoSWSDS]

When I set up my home computer to be able to access the VPN at work, the network at work was using 192.168.0.* and so was my home network. I logged into my home router and changed the network IPs to be 192.168.250.*. You'll have better luck changing your home network than you will getting the network admin at work to change their network so you can use their VPN.

Later, my work changed their network to 192.168.1.*. I didn't have to change my home network to still be able to access theirs because I used 250 for the third octet. My thinking was that the chances of someone using 250 for the third octet were slim to none, so no matter what they did at work, I wouldn't have to redo my network.

CogoSWSDS

[computeguy]

IT Manager here.


When setting up a VPN... both sides have to have different ip address ranges. If your work addr is
192.168.0.x then your home can be anything other than that one....

It won't work if both sides have the same addr range.

[Soopafresh]

Thanks, guys. That basically confirms my thoughts.