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see which DNS(s) is used

Posted: Thu Jun 27, 2019 12:43 am
by AlexanderK
Hello!

I connect to an OpenVPN server (v2.4.3) with Viscosity 1.7.16 on a Mac (10.13.4).

The server has settings like this:
push "dhcp-option DNS A.B.C.D"
push "dhcp-option DNS E.F.G.H"

It looks though like not all viscosity clients honor this.
How can i see which DNS is used by the computer when i am connected to the VPN?
I tried looking in settings->network->... but the i just see wifi, thunderbolt and such,
shouldnt i see a VPN-connection of some sort there too?
If not there, where?

wbr / Alex

Re: see which DNS(s) is used

Posted: Thu Jun 27, 2019 12:16 pm
by James
Hi Alex,

Viscosity displays which DNS servers are set for the VPN connection in the Details window. Simply select the Details option from Viscosity's main menu, and then click on the centre icon (the two arrows) to see connection details.

For a full look at a computer's DNS settings, the "scutil" command line tool can be used:
https://www.sparklabs.com/support/kb/article/configuring-dns-and-wins-settings/#checking-which-dns-servers-are-being-used

Please note that Viscosity's DNS support is pretty bullet proof: in almost all instances of users reporting DNS isn't working the wrong DNS Mode is set for the connection:
https://www.sparklabs.com/support/kb/article/configuring-dns-and-wins-settings/#dns-modes

You can see what DNS Mode is currently being used in the connection log:
https://www.sparklabs.com/support/kb/article/viewing-the-openvpn-log/

Cheers,
James

Re: see which DNS(s) is used

Posted: Thu Jun 04, 2020 8:15 pm
by AlexanderK
Btw, thanks for the answer! :)

Another thing, if i see in the details-window that a computer seems to have switched the primary and secondary DNS servers, what could be the cause of this?

In the OpenVPN server i have:
push "dhcp-option DNS 1.2.3.4"
push "dhcp-option DNS 5.6.7.8"

But in a client (but only in one, all other 40 or so clients work fine) i see:
DNS Server/s: 5.6.7.8, 1.2.3.4

So what could cause a client to switch between primary and secondary DNS like this?

Re: see which DNS(s) is used

Posted: Fri Jun 05, 2020 12:42 pm
by James
So what could cause a client to switch between primary and secondary DNS like this?
Check to see whether one or more of the DNS servers are also specified locally in the connection's configuration on that machine (and if so try removing them):
https://www.sparklabs.com/support/kb/ar ... -viscosity

macOS may also invalidate a DNS server if it's not reachable (can't be contacted). In which case you should also check for any routes or firewall software that could be preventing access to that DNS server.

Cheers,
James

Re: see which DNS(s) is used

Posted: Tue Jun 09, 2020 7:06 pm
by AlexanderK
Thanks a lot for the help! Will check these things!