Can someone please check my VPN DNS setup

gregeeh · Apr 29, 2018, 7:03 AM

Hi all,

I'm new to pfSense and have setup a VPN Client to connect with my VPN Provider. All LAN traffic is going via the VPN. It is all working but I'm concerned about if I have setup the DNS correctly. Below are the settings.

The DNS Leak Test looks fine to me, however I have entries like below in Syslog which seems to suggest the OpenDNS Servers are being used and not those from my VPN Provider as shown in the DNS Leak Test Results.

<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: query[PTR] 1.10.168.192.in-addr.arpa from 192.168.10.2
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: /etc/hosts 192.168.10.1 is pfsense.localdomain
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: query[A] app.bitly.com from 192.168.10.13
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: forwarded app.bitly.com to 208.67.222.222
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: forwarded app.bitly.com to 208.67.222.220
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: reply app.bitly.com is <cname>
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: reply bitly.com is 67.199.248.14
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: reply bitly.com is 67.199.248.15
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: query[AAAA] bitly.com from 192.168.10.13
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: forwarded bitly.com to 208.67.222.222
<30>1 2018-04-29T16:34:02+10:00 pfsense.localdomain dnsmasq 17991 - - dnsmasq[17991]: forwarded bitly.com to 208.67.222.220</cname>

Comments greatly appreciated.

TIA

Greg

Derelict · Apr 29, 2018, 5:24 PM

When you query the local DNS server and it has to go out to the internet to get an answer that query is NOT policy routed because it does NOT arrive into the LAN interface. It originates on the firewall itself.

You only gave about half the information needed. You left out what DNS servers the clients are actually told to use.

If quelling "DNS leaks" is your goal, the best thing to do is to have the clients being routed out the VPN use DNS servers out on the internet and not anything on pfSense itself. This would be set statically on each client, in the DHCP server they use, or in a DHCP static mapping for certain hosts.

gregeeh · Apr 29, 2018, 9:19 PM

@Derelict:

You only gave about half the information needed. You left out what DNS servers the clients are actually told to use.

The clients are using the IP of pfSense as their DNS Servers. Sorry about not stating this.

Derelict · Apr 29, 2018, 9:55 PM

Then that's your problem. Set them to use external DNS servers or tell them to use an inside DNS server (as in not on the firewall itself) and policy route the queries from that server out the VPN.

gregeeh · Apr 29, 2018, 11:00 PM

@Derelict:

Then that's your problem. Set them to use external DNS servers or tell them to use an inside DNS server (as in not on the firewall itself) and policy route the queries from that server out the VPN.

Thank you for your time and your explaination it is greatly appreciated. As my VPN is with VPN.AC I followed their instructions :
https://vpn.ac/knowledgebase/63/OpenVPN-on-pfSense.html

Sorry for the noob question but I still do not understand why the DNS Leak Test websites pass if I have set this up incorrectly. :-[

Derelict · Apr 29, 2018, 11:49 PM

That DNS test you posted was NOT passing correctly so what are you talking about?

Man, am I tired of these DNS leak threads.

johnpoz · Apr 30, 2018, 10:12 AM

"Man, am I tired of these DNS leak threads."

You can say that again ;)

bcruze · Apr 30, 2018, 12:40 PM

try viewing this website for the PIA DNS servers: https://helpdesk.privateinternetaccess.com/hc/en-us/articles/219460397-How-to-change-DNS-settings-in-Windows

then go to system > general. and add them there

THEN go to services > dhcp server > servers / DNS. add them there

post again after you have rebooted the pfsense router

i have found adding DNS to the general tab is what causes the leaks.. when i use the PIA DNS servers on the actual SERVER DNS it fixes leaks for me.

this is for PIA and AIRVPN… i also do not use the DNS forwarding tab. its disabled, i use the DNS resolver tab

not a pro, just sharing my experience with my setup