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First post. Hopefully I've explained everything clearly.

I have PC that I use infrequently. I have Ubuntu Mate 16.04.3 installed (I think 16.04.2 was what was installed initially, but up was updated).

On the machine I run the internet through a VPN service, for which I use via OpenVPN. I have the DNS running through Network Manager. I was happy I had a secure VPN set up, after checking at https://ipleak.net/ I didn't have any leaks - I took care of things like turning off WebRTC, disallowing IPv6, and I also used UFW to block off all traffic that didn't run through the VPN, so if the VPN is down, no internet.

So, everything seemed fine, I had a machine that I thought had a secure VPN set-up...until about 4 weeks ago (it might have happened earlier and I hadn't noticed), because now, on, checking at ipleak, my PC has developed a mysterious DNS leak. I end up with "DNS Addresses - 2 servers" instead of one, and one of those servers, although isn't my unmasked ISP IP address itself, it is, on checking, owned by my regular ISP, so I assume it's probably my ISP's DNS server? (Sorry if I'm getting any terminology slightly wrong, as I don't have massive experience/knowledge of VPN systems or DNS).

Also, one other slight oddity and concern that I think is worth mentioning on is that I now don't seem to be able to turn off auto-updates, and in spite of this, the DNS leak "bug" has not been rectified. If I go into the "Updates" tab under "Software & Updates" in Administration, I try to make changes in "Automatically check for updates" drop down menu, from "Daily" (which I'm not sure I actually set it to) and try to change it to "Fortnightly" it refuses and stays set at "Daily". Same goes for "When there security updates" when I try to change it to "Download and install automatically" to "Display Immediately", it also refuses to change. When I tried to make such changes in the past, not unsurprisingly, I got an "Authenticate" dialog popping up, asking me to give my administrator password. No such dialog pops up anymore, it now just refuses to let me make any changes. I thought it was worth a mention, just in case there's a connection.

Might be also worth mentioning that I have Cinnamon desktop also installed, which I'm currently using instead of Mate - I've checked though, and it is misbehaving in both Cinnamon and Mate, so I don't think that could be the issue.

So, guys, any idea why my machine has suddenly developed a DNS leak? Is there perhaps a new Network Manager option I now have to change to get my DNS back on the secure side?

Oh, and as a couple of side questions that have been bugging me. I use Network Manager for my DNS , but where does Network Manager get it's DNS information from? Also, is there a way of setting OpenVPN to auto-reconnect to my VPN provider if there's a disconnect when using it the way I do, through Network Manager?

Thank you for any help.

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  • On my Ubuntu 16.04 LTS MATE I use NetworkManager dispatcher (see my answer) to prevent DNS-leaks. Edit ROUTER_IP variable.
    – N0rbert
    Jul 8, 2018 at 12:07

2 Answers 2

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Thanks guys.

@Norbert. I'll try that out, looks interesting.

I actually found my solution after digging into related posts on the right. Which lead to this:

https://bugs.launchpad.net/ubuntu/+source/openvpn/+bug/1211110

Post #92 providing the solution. It worked!

Seems it's a long running problem.

@heynnema

Not sure to go with google's nameservers or my VPN provider's. Using the solution above, before seeing your post, I've set my VPN providers. Might stick with that, as my eggs are already in their privacy basket, if you know what I mean. But I guess there might an advantage to using Google's I'm not aware of.

Quite what broke my DNS lookup in the first place I might never know, I guess, but I assume it was probably some update to Network Manager. That's the second time NM's messed up my internet, last year it took out my wifi stick with it's MAC spoofing update. Very frustrating.

I guess changing my update settings is an unrelated problem. That's another puzzle to be solved.

I assume before things went wrong that my VPN provider was providing the DNS via the IP address of their VPN service, and that's what NM was using to get the DNS.

Could really do with a monitor of DNS leaks in software to do the job that ipleak.net and the like provide, so you know quickly when things have gone wrong by an alert.

Still have to hunt out a solution to auto-reconnect to the VPN.

Thanks guys.

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  • Using the fix from post #92, how did you determine what DNS IP to use? Also, didn't the second part of my answer address the auto-connect?
    – heynnema
    Jul 9, 2018 at 14:10
  • My reply was too big for a comment reply to you, so I've replied further down. Thanks.
    – Nico Mundo
    Jul 17, 2018 at 11:51
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@Heynnema

Hi, sorry for the late reply. Not totally familiar with this system, yet, but this post was too big for a "comment" reply direct to you, so I've ended up replying to myself again.

I got the DNS servers of my VPN provider by googling after seeing post #92, and found it on a forum post by one of the staff.

Your reply post doesn't seem to be visible now, but thankfully I'd saved replies. Yes, I tried it, but I have a couple of problems with that solution. The first is I sometimes connect to an alternative VPN server, if I'm having reliability issues, and that would tie my connection to one - I know I could keep going into the config to switch it, but that would be a pain. It also doesn't solve the issue that if the VPN connection fails while the regular internet connection stays connected (an actually more common occurrence, in my experience), it doesn't try to reconnect to the VPN in that situation.

It would be better if NM remembered the VPN it's currently connected to, and automatically retry connect to that VPN, if the connection fails - unless the user has opted to disconnect it themselves, IMO. I think that's the sort of option I'm looking for, if it exists.

Thanks.

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