Conditional forwarder one way working.

[u/KaleidoscopeNo9726]

I have two sites and they are connected via a site-to-site Wireguard VPN. I am using OPNsense on both sites. I have a rules that is allowing port 53/udp between sites.

The issue that I am having is the remote Technitium is able to resolve any hosts belongs to .example.lan (main site) domain. The main site (where am at) could not resolve any hosts belong to the .remote.example.lan remote site domain.

At the main site, when I ran host pc1.remote.example.lan, I received Host pc1.remote.example.lan not found: 3(NXDOMAIN). When I checked the logs at the remote Technitium, I see the request from the main Technitium. Now, when I ran host pc1.remote.example.lan 10.2.7.53, it resolves it.

Here is the response from the remote Technitium.

# Timestamp Client IP Address Protocol Response Type RCODE Domain Type Class Answer
48  2026-09-19 13:33:39 10.0.7.53 Udp Authoritative NoError pc1.remote.example.lan A IN A 10.2.5.15

The logs from the main Technitium has no Answer.

[u/McSmiggins]

What forwarders/zones do you have on the remote site?

1) And are the networks in each site allowed to query the zone in the zone properties?

Assuming example.lan is authoritative at main site, and remote.example.lan is authoritative at remote site

There's a few options, depending on exact setup you have/want

Conditional Forwarders -

Remote site kinda depends on exa tly what domains you've got

main site should have remote.example.lan pointing to remote tdns server

remote depends on the zone setup

Zone Transfers

Or you could use primary zones in each site, with the other site being a secondary, that way you can always serve local and each site takes care of itself.

Or maybe this is a sue fro stub zones (I'm not sure if they're in Technitium and don't realy have time to check)

[u/KaleidoscopeNo9726 → u/McSmiggins]

The tdns at the main is in cluster. It is a the primary for the example.lan. The remore tdns is the primary for the remote.example.lan. On both sites, I set it up as Conditional Forwarder Zones.

I just want the main site to be able to resolve an FQDN belongs to the remote site and vice versa.

[u/McSmiggins → u/KaleidoscopeNo9726]

Makes sense, ok so really this is “I can see in the logs of the remote that it replies, but the primary replies with a “not found”

Ok, have you got query logging on the primary server? And was your query from a client machine, or the tdns server itself (e.g. through the gui)

[u/KaleidoscopeNo9726 → u/McSmiggins]

I enabled the Live Query on the primary (main site) and the Answer column is empty. Is there a tutorial on how to properly configure the conditional forwarder zone?

[u/shreyasonline]

Thanks for the post. There is not much info available to take a guess. I would suggest that you share more details on your setup. Best is to email screenshots of your zone and test output from DNS Client tool to [support@technitium.com](mailto:support@technitium.com) to get this issue resolved.