I just upgraded to OSX Mountain Lion and had some trouble this morning getting my OpenVPN connection (using Tunnelblick) to work. It would connect, but the DNS resolving was unstable. I managed to get it to work on the latest stable by changing the DNS-server setting to ‘set nameserver 3.0b10’ but then internet traffic would not work. The best solution for me at the moment is to upgrade to Beta release 3.3beta16 3.3beta18.
After upgrading, everything works as expected!
More info:
Update: see this blog I wrote as well (experience after one week)
Update 2: TunnelBlick 3.3 beta 18 has just been released and the release notes state it has fixed more Mountain Lion bugs.
Remi Bergsma's blog 
Thanks this was helpful!
Good to hear that, you’re welcome!
you saved my life!
Nice it works for you too 🙂
Thanks SO much for posting this, I had to work from home today and noticed my connection would succeed at first but it kept trying to reconnect immediately after. I upgraded to beta version as suggested and now it works!
Great! 🙂