[Solved] Can ping ip addresses but no Name Resolution

[dlubart]

My wife uses OpenVPN to connect to her work network. Several times in the past year, her machine has suddenly lost internet access (as per the icon in the system tray). What really happens is that it has lost DNS so she can ping an IP address but cannot resolve names so no browsing. Pretty much renders a PC into a brick these days.

What's worse is that all of the usual steps were useless. Manually set DNS servers to 1.1.1.1 and 8.8.8.8 in IP4 properties. Reset the network card, tried /flushdns. Reinstalled network drivers. Uninstalled OpenVPN. Even updated Windows. The machine was permanently unable to browse. Ipconfig /all showed DNS servers as 1.1.1.1 and 8.8.8.8 but nothing. We brought the machine to another network to eliminate any chance of our router being complicit (which I knew wasn't the case, but her work IT department desperately insisted must be the issue). The only thing that worked the first time was a complete clean re-install of Windows (in desperation because we had a time crunch).

So it happened again this past week not only on her desktop, but also on her laptop (the decision to expose a second machine to this is one I did not endorse) and I had a little more time to dig. Eventually, I decided to install WireShark to analyze the packets as I tried to ping. To my surprise, the machine was still trying to use a private ip DNS server that definitely wasn't part of my local network and was not what the network card properties was set to use. I'm assuming it was the DNS server for her workplace, which obviously was not accessible from our house when not running the VPN client. From there it was simple to search it out in the registry and find an entry that had effectively hijacked my DNS. Deleting that entry cleared the problem immediately.

My best summary is that OpenVPN is not cleaning things up properly. Even if the client crashes, it should clean that entry out the next time it is closed and CERTAINLY when it is uninstalled. I have seen quite a few similar posts about this type of issue, but never this particular solutions, so I wanted to get this out here for people to try in similar circumstances. I would also encourage OpenVPN to look into this as a critical bug.

Hope this helps.

-Dan