TCP_SILENTLY_BLOCKED

error

Large answers for this domain never arrive, which usually means something is blocking DNS over TCP.

Something is wrong and mail or certificates are affected.

How we know

blocked.test
Answers over UDP with the TC bit set, then accepts the TCP retry and never replies — the resolver-visible shape of a middlebox blocking TCP port 53. No zone can express it, so it is an in-process listener rather than an nsd container.