Have you asked them to setup PTR records? We usually do it for our clients, so I’ve no idea how others handle it -- Mr Michele Neylon Blacknight Solutions Hosting, Colocation & Domains https://www.blacknight.com/ https://blacknight.blog/ Intl. +353 (0) 59 9183072 Direct Dial: +353 (0)59 9183090 Personal blog: https://michele.blog/ Some thoughts: https://ceo.hosting/ ------------------------------- Blacknight Internet Solutions Ltd, Unit 12A,Barrowside Business Park,Sleaty Road,Graiguecullen,Carlow,R93 X265,Ireland Company No.: 370845 I have sent this email at a time that is convenient for me. I do not expect you to respond to it outside of your usual working hours. From: anti-abuse-wg <anti-abuse-wg-bounces@ripe.net> on behalf of Alessandro Vesely <vesely@tana.it> Date: Friday, 5 April 2024 at 13:01 To: anti-abuse-wg <anti-abuse-wg@ripe.net> Subject: [anti-abuse-wg] Reverse DNS delegations [EXTERNAL EMAIL] Please use caution when opening attachments from unrecognised sources. 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 -- -- To unsubscribe from this mailing list, get a password reminder, or change your subscription options, please visit: https://lists.ripe.net/mailman/listinfo/anti-abuse-wg