After troubleshooting OpenVPN issues for the past few days; I figured I'd share my results to save somebody else the headache in the future. Here's what I found...
I recently installed a Nighthawk R7350 as my main home router. I updated the firmware to V1.2.0.92_1.0.1, which was the latest version at the time. One of the features I wanted to use was OpenVPN to connect my mobile phone to my home network while I'm away from home. However, while I could connect to OpenVPN using the instructions provided online, I could not access any home devices or the Internet.
After LOTS of troubleshooting I noticed that the router seems to hand out 192.168.2.X IP addresses to VPN clients. The problem was that I changed my router's LAN settings to also use the 192.168.2.0/24 address space. So, when my iPhone connected to OpenVPN in TUN (routing) mode; the router was trying to route between two networks with the same address space. Or at least this is what appeared to be happening. And there doesn't seem to be a way to change the OpenVPN server configurations to mitigate this.
After changing my router's LAN configuration to use the 192.168.1.0/24 address space everything seemed to work. I'm not sure if this is a bug or if I missed a warning message somewhere in the documentation that states you can't use the 192.168.2.0/24 address space for the LAN if you plan to use OpenVPN. In either case; hopefully this post will help somebody else out there that runs into the same problem.
After troubleshooting OpenVPN issues for the past few days; I figured I'd share my results to save somebody else the headache in the future. Here's what I found...
I recently installed a Nighthawk R7350 as my main home router. I updated the firmware to V1.2.0.92_1.0.1, which was the latest version at the time. One of the features I wanted to use was OpenVPN to connect my mobile phone to my home network while I'm away from home. However, while I could connect to OpenVPN using the instructions provided online, I could not access any home devices or the Internet.
After LOTS of troubleshooting I noticed that the router seems to hand out 192.168.2.X IP addresses to VPN clients. The problem was that I changed my router's LAN settings to also use the 192.168.2.0/24 address space. So, when my iPhone connected to OpenVPN in TUN (routing) mode; the router was trying to route between two networks with the same address space. Or at least this is what appeared to be happening. And there doesn't seem to be a way to change the OpenVPN server configurations to mitigate this.
After changing my router's LAN configuration to use the 192.168.1.0/24 address space everything seemed to work. I'm not sure if this is a bug or if I missed a warning message somewhere in the documentation that states you can't use the 192.168.2.0/24 address space for the LAN if you plan to use OpenVPN. In either case; hopefully this post will help somebody else out there that runs into the same problem.
-Brian
Your description is good and your observation is correct. At one time, buried in the OpenVPN web site, there was a planning document for configuring the address space on the network where you are running the OpenVPN server. When connected, the network where the server is running and the network where the client is connected from will not tolerate address conflicts. Use of the 192.168.1.X address space is extremely common for either end and conflicts easily arise. The planning document recommended not using the 192.168.1.X address space for the network where the server resides.
