Cannot use OpenVPN Connect client when ZeroTier One service is running

I have been using both ZeroTier and OpenVPN together for some time now for different reasons on Windows 10. ZeroTier is used for remote clients to backup data, while OpenVPN requires login credentials to access internal networks. Both are totally separate.

I updated the OpenVPN Connect client from 3.2.3 to 3.3.1. After doing this the client hangs upon attempted connection to the OpenVPN server.

Using Wireshark, I determined that this is due to OVPN traffic being sent over the ZeroTier One network adapter. Revert back to the older version of the client or disable the ZeroTier One service, and OpenVPN works again.

This is basically the same issue as described here:
Can't connect to OpenVPN when joined to ZeroTier One network on Windows 10

The above post had no replies, but it looks like the issue is not tied to an OpenVPN client version in any way…but the act of moving to a different version.

Any direction on what I could do here to get both working again would be great.

thanks for writing. It seems like there should be a way to tell OpenVPN to not do that?

I guess there’s a possibility there’s some kind of driver conflict. What if you rerun the zerotier installer? Update to 1.6.5 if you’re not on that already.

Thanks for the suggestion. I re-installed ZT 1.6.4 but observed the same behavior.
I just uninstalled and then installed 1.6.5 and still see the same issue unfortunately.

Very bizarre, for some reason something is now forcing traffic from the OpenVPN client to route through the ZT gateway rather than through my laptop wireless adapter.

Posting an update in case anyone else encounters something like this…

I also raised this issue on the OpenVPN forums, and it looks like they have found a possible issue within their client:
OpenVPN Connect client and ZeroTier - OpenVPN Support Forum

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