How to prevent Juniper Network Connect breaking DNS resolutions

Question

Juniper Network Connect has been an issue on 64bit linux for quite sometime. I have found 2 solutions to the Java issue (Solution 1 and 2) but now I am struggling with a new issue.

Network connect makes changes directly to the /etc/resolv.conf file. This causes issues with the newer way that Ubuntu does DNS resolutions which is to point DNS to the local resolver/cacher: dnsmasq. Once NC disconnects and you change networks, eg go from office to home then DNS stops working correctly. What happens is that NC deletes the /etc/resolv.conf file which is actually symlinked to /run/resolvconf/resolv.conf. Whats worse is that NC actually deletes the original file not the link. So when you try to restore the file with:

sudo ln -s /run/resolvconf/resolv.conf /etc/resolv.conf

It fails as /run/resolvconf/resolv.conf is now gone. re-installing resolvconf does not fix it and neither does running resolvconf. So the best way I have found so far is to first backup /run/resolvconf/resolv.conf to another location. After you disconnect NC I then run a script that removes /etc/resolv.conf, replaces the deleted /run/resolvconf/resolv.conf and then links it's back to /etc again.

Does anyone know a way to avoid this or do I pretty much have he best "fix" in place already? Any way to prevent NC from breaking it in the first place.

Oh how I wish Juniper would sort their issues out. Juniper has been notoriously HORRIBLE on Linux and 64bit especially for over 4 years now.

Answer 1

I would expect that you do not need to reinstall the package. Just restarting resolvconf should fix the problem:

sudo service resolvconf restart

If that does not happen to work, in addition you can try restarting the network service which will try to write a new set of values to /etc/resolv.conf

sudo service network restart

Answer 2

After Network Connect has been stopped it suffices to do the following.

sudo ln -s ../run/resolvconf/resolv.conf /etc/resolv.conf
sudo resolvconf -u  # Regenerate /run/resolvconf/resolv.conf

You don't need to back up /run/resolvconf/resolv.conf beforehand.

Answer 3

First: clicking the Sign Out button in the Network Connect window (the window that shows the VPN IP while connected) and

Then clicking on the Sign Out button in the logged-in web page avoids this problem.

Please indicate in comment if this works or not.

Thanks

Answer 4

The best way to fix the /etc/resolv.conf symlink is to run

sudo dpkg-reconfigure resolvconf

and answer YES to prepare resolv.conf for dynamic updates.