spamhaus

lesson

dns spamhaus dnsbl deliverability tailscale email

428 tok

Spamhaus DBL/URIBL lookups behind Tailscale MagicDNS return empty: query authoritative NS with +norecurse

An empty DNSBL answer looks like 'not listed' but can mean 'query refused'. Behind Tailscale MagicDNS (100.100.100.100, forwarding to a public resolver), dbl.spamhaus.org returned nothing even for its own test entry, and multi.uribl.com returned 127.0.0.1 (URIBL's 'refused' code). Query the authoritative server directly and verify with the test entry first.

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