After last week’s posts about VPN Clients, I had some questions about the VPN connections themselves. This is a strange one. It’s very hard to describe without getting too specific, so it may not make good blog-fodder, but hopefully this post will help somebody out. The problem typically goes something like this: I set up a VPN connection to my office. I have the software, whether it’s the Cisco VPN Client, or the SonicWall Global VPN Client, installed on my computer. My connection details are correct, the VPN prompts me for a name and password and takes what I provide. Everything is working up until that point. But then whatever resource I try to use, whether it’s a Terminal Server, a mapped network drive, or a software application on the other side of the VPN, it just doesn’t work.
The resolution is easier than the description. Your local IP range is conflicting with the remote IP schema. It’s not as bad as it sounds. Basically, your home router, out of the box, is most likely configured to give your devices an IP address of 192.168.1.x. If your work or office network was configured the same way, then when you punch in a device IP address when you’re connected to the VPN, then the computer gets confused and doesn’t know whether it should be looking around your house for a certain server or device, or if it should be looking on the other side of the VPN.
The easy fix is to change the IP address of your router. Unless you’ve set static IP addresses, all of your other home devices will automatically pick up the new IP addresses and fix themselves, you shouldn’t have to do anything once you change the router setting itself. For instance, in a Linksys router, you’ll just go to the control page (http://192.168.1.1) and login (probably no username and the password admin, then on the main page, change the local IP address of the router from 192.168.1.1 to pretty much “anything else” in that third octet. Example: 192.168.101.1. It may not make a ton of sense, but whoever is on the other end of the VPN may be able to help you out, and if they weren’t sure what the problem was, this should give them some guidance.