Hi all, what's the policy for reverse delegation? My provider assigned me a 2a02:29e1:500:6c00::/56. Great. However they didn't delegate reverse DNS. Indeed, their own 2a02:29e1::/32 has no delegations: ; <<>> DiG 9.18.24-1-Debian <<>> 1.e.9.2.2.0.a.2.ip6.arpa ns ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 19800 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 1232 ; COOKIE: cad8ae482b0e559c01000000660fe49763aa815e05fda159 (good) ;; QUESTION SECTION: ;1.e.9.2.2.0.a.2.ip6.arpa. IN NS ;; AUTHORITY SECTION: 0.a.2.ip6.arpa. 3600 IN SOA pri.authdns.ripe.net. dns.ripe.net. 1712314758 3600 600 864000 3600 Now there are mail servers which reject mail if they don't find a matching PTR: <<< 554 resimta-c2p-559421.sys.comcast.net resimta-c2p-559421.sys.comcast.net 2a02:29e1:500:6c00::4 Comcast requires that all mail servers must have a PTR record with a valid Reverse DNS entry. Currently your mail server does not fill that requirement. For more information, refer to: https://postmaster.comcast.net/smtp-error-codes.php#554 Why isn't it possible to gain a delegation by proving number assignment? Best Ale --