Local vs VPN DNS Name Resolution

NOYB

continue?? this thread was from 2014 ;)

Continuing from the other thread that we had hijacked.
Yes this thread is from 2014. Is my thread that I started on the specific subject of local vs. VPN DNS name resolution, or more concisely put "DNS leakage", and previously there had not been a solid resolution to the issue. So it is a very direct fit for the newly implemented "block-outside-dns" option discussion.

johnpoz

So what exactly do you want again.

So you want to use your vpn dns, but not your local dns to resolve stuff other than local? Is that what your after? Yeah not going to happen.. How do you control your client to only ask the local dns where its at for stuff that is local, and ask your vpn dns for everything else..

Or am I missing something?

kpa

I believe the following is possible when the client is MS Windows:

The TUN/TAP adapter on the client gets an adapter specific DNS domain name.
The DNS resolvers pushed from the OpenVPN server are associated with the TUN/TAP adapter on the client.
DNS names ending with this adapter specific DNS domain name get resolved by the adapter specific DNS forwarders which can be directed over the VPN tunnel using routes.

Of course none of this will work on any other operating system.

johnpoz

"DNS names ending with this adapter specific DNS domain name get resolved by the adapter specific DNS forwarders which can be directed over the VPN tunnel using routes."

Where did you get that idea from?? Where is the MS article that says dns is used based upon connection specific domains or search order?

That is not how it works…
https://technet.microsoft.com/en-us/library/dn305896.aspx

Now per the above there was an API that allows a program do do name resolution out a specific interface... Are you writing the program to tell your browser what to resolve and from where to use this API? Or any of your other applications you might use? They made some changes to the binding order of how name resolution is done. But I have not read anywhere that if I put a specific domain name on a specific interface that that is the dns servers it uses for name resolution of that domain name.. But will for sure test it on monday when get to work.. Because what I can tell you from every single day using vpn into home network and resolving different things both locally and remotely.. That is not how it works on windows 7 for sure.. But sure I will double check it..

NOYB

Pippin,
I'm thinking/wondering if maybe the name resolution you are getting for local services is WINS. With the block outside dns enabled I can for example ping via local host name even though there is no DNS resolution of the name. Though there is a slight second or two delay in resolving the address since WINS is later in the resolution order.

John,
Pretty much. Yes, I want to have my cake and eat it too. I want local names resolution for local resources only, and VPN provided DNS only for everything else. I know it doesn't work like that. But that's how I want it to work.

Pippin

Will try to find why its working for me. That machine as I just discovered, is getting detected through NetBIOS so yes maybe its WINS.

Under Network select View-Details, then right click on the columns (Name-Category-Workgroup-etc.) and select "Discovery Method".
Then you can see how they`re discovered, obviously :o

I hope thats clear enough because I dont have English version of Windows :)