When I queried the authoritative server directly it worked: ;; QUESTION SECTION: ;111.250.179.17.in-addr.arpa. IN PTR
;; ANSWER SECTION: 111.250.179.17.in-addr.arpa. 86400 IN PTR rn2-msbadger07105.apple.com. ;; Query time: 62 msec ;; SERVER: 17.47.176.10#53(17.47.176.10) I would recommend that you too do a dig @ and see what you get. If it works then you can start examining your on prim configs .. if it does not work then you need to be using wireshark to figure out what is happening to the traffic. Either way you need to first break your troubleshooting into two parts .. on prim vs off prim and proceed from there. Good hunting. John -----Original Message----- From: bind-users [mailto:bind-users-boun...@lists.isc.org] On Behalf Of Julien Salort Sent: Thursday, March 25, 2021 12:11 PM To: bind-users@lists.isc.org Subject: Timeout setting Hello, I have a VPS running postfix and bind9. Bind is used as a recursive resolver, in particular to be able to query anti-spam database. Postfix is also configured to reject incoming connections from servers with no reverse dns. It works great overall, but sometimes legitimate messages get rejected because the reverse dns query fails. Here is an example (anonymized email and host address): In mail.log: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [17.179.250.111]; from=<developer_boun...@insideapple.apple.com> to=<x...@example.com> proto=ESMTP helo=<rn2-msbadger07105.apple.com> (total: 1) In named journal: mars 02 01:14:20 example.com named[2756114]: client @0x7f3a0808c750 127.0.0.1#43646 (111.250.179.17.in-addr.arpa): query: 111.250.179.17.in-addr.arpa IN PTR +E(0) (127.0.0.1) mars 02 01:14:25 example.com named[2756114]: client @0x7f3a08079d00 127.0.0.1#43646 (111.250.179.17.in-addr.arpa): query: 111.250.179.17.in-addr.arpa IN PTR +E(0) (127.0.0.1) mars 02 01:14:32 example.com named[2756114]: client @0x7f3a0808c750 127.0.0.1#43646 (111.250.179.17.in-addr.arpa): query failed (timed out) for 111.250.179.17.in-addr.arpa/IN/PTR at query.c:6883 mars 02 01:14:32 example.com named[2756114]: client @0x7f3a000d5110 127.0.0.1#49520 (insideapple.apple.com): query: insideapple.apple.com IN MX + (127.0.0.1) So there is a timeout. Now if I try again: $ dig -x 17.179.250.111 @localhost +short rn2-msbadger07105.apple.com. So it seems that it is just that sometimes the query takes a bit longer... Is there a general advice regarding timeout for bind? Should I just choose a longer timeout? Or is there a reason for the default value? I did not have such problems when I was using the ISP dns server instead of a local recursive resolver. So I was wondering if the configuration is sub-optimal somehow... Thank you, Cheers, Julien _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users