ANSWERED I'm experiencing a DNS leak, and it might have something to do with IPv4

[dsiu98 0]

I'm using EndeavourOS, with Eddie GUI 2.24.6

When I go to Eddie GUI -> Settings -> Networking and make sure neither IPv4 or IPv6 is blocked, then disconnect and reconnect, then visit https://ipleak.net/ , the results show up with 4 DNS servers:
1: IPv4 of my ISP's DNS server
2: IPv6 of my ISP's DNS server
3: IPv4 of AirVPN's DNS server
4: IPv6 of AirVPN's DNS server

But when I go to Eddie GUI -> Settings -> Networking and make sure that IPv6 is blocked but IPv4 isn't, then repeat the rest, the results only show 2 DNS servers:
1: IPv4 of my ISP's DNS server
2: IPv6 of my ISP's DNS server

Throughout all of this, /etc/resolv.conf read my router-assigned private IP address (of course, when I disabled IPv6, it only read the IPv4 address)

I tried blocking IPv4, but Eddie tells me it hasn't been implemented yet.
I tried going to Eddie GUI -> Settings -> DNS and setting various (both IPv4 and IPv6) addresses as my DNS server, including 10.4.0.1 and censurfriDNS, (which successfully overwrote /etc/resolv.conf) but the results are the same.

What am I doing wrong? Nothing I tried changed my results except blocking IPv4, which only made the leak worse.

[Staff 10111]

  On 3/26/2025 at 11:27 AM, dsiu98 said:

Throughout all of this, /etc/resolv.conf read my router-assigned private IP address

Hello!

This is unexpected, and it could be the cause of the problem. Eddie should modify /etc/resolv.conf if you have Eddie configured to use VPN DNS exclusively (which is the default setting). Can you verify whether systemd-resolved is running in your system (anyway Eddie must be capable to manage any systemd-resolved working mode)? Can you also publish Eddie's system report generated while the problem is ongoing? Please see here:
https://airvpn.org/forums/topic/50663-youve-been-asked-for-a-support-filesystem-report-%E2%80%93-heres-what-to-do/

Last but not least, please publish the output of the following commands:

ls -l /etc/resolv.conf
cat /etc/resolv.conf

while the system is connected to the VPN.

Kind regards
 

[dsiu98 0]

I have since fixed it!! The problem was Firefox using DoH by default.
I fixed it by going to about:config -> network.trr.mode -> 5
But thanks for offering your help!

[Staff 10111]

  On 3/28/2025 at 12:18 PM, dsiu98 said:

I have since fixed it!! The problem was Firefox using DoH by default.
I fixed it by going to about:config -> network.trr.mode -> 5
But thanks for offering your help!

Hello!

Excellent, and thank you for having let us know. However, there's something unexplained, because with Firefox DNS over HTTPS enabled you shouldn't have seen your ISP DNS addresses:
 

  On 3/26/2025 at 11:27 AM, dsiu98 said:

1: IPv4 of my ISP's DNS server
2: IPv6 of my ISP's DNS server

Furthermore, your /etc/resolv.conf file while connected to the VPN showed your router address as the name server address, and this is unexplained as well.

Maybe you just gathered the wrong information earlier (for example you took /etc/resolv.conf content when the system was not connected to the VPN) and everything is fine, but just to stay on the safe side keep all of the above in mind.

Kind regards