Is there anyone from duke.edu on this list? I am having problems with IPv6 on one of their sub-delegations causing mail delays. Trying to go through the front door writes me off with "not our problem". dm.duke.edu. 21600 IN NS nameserver1.mc.duke.edu. dm.duke.edu. 21600 IN NS nameserver2.mc.duke.edu. ;; Received 135 bytes from 152.3.105.232#53(dns-auth-02.oit.duke.edu) in 76 ms nameserver1.mc.duke.edu has address 152.16.1.4 nameserver1.mc.duke.edu has IPv6 address 2620:0:691:dc50::4 nameserver2.mc.duke.edu has address 152.16.1.12 nameserver2.mc.duke.edu has IPv6 address 2620:0:691:dc57::12 Works on IPv4: ; <<>> DiG 9.10.3-P4-Debian <<>> MX dm.duke.edu @152.16.1.4 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4622 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 1232 ; OPT=15: 00 12 ("..") ;; QUESTION SECTION: ;dm.duke.edu. IN MX ;; ANSWER SECTION: dm.duke.edu. 3600 IN MX 10 mx.oit.duke.edu. ;; AUTHORITY SECTION: dm.duke.edu. 86400 IN NS nameserver1.mc.duke.edu. dm.duke.edu. 86400 IN NS nameserver2.mc.duke.edu. ;; Query time: 77 msec ;; SERVER: 152.16.1.4#53(152.16.1.4) ;; WHEN: Thu Sep 19 06:37:13 PDT 2024 ;; MSG SIZE rcvd: 140 ; <<>> DiG 9.10.3-P4-Debian <<>> MX dm.duke.edu @152.16.1.12 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7136 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 1232 ; OPT=15: 00 12 ("..") ;; QUESTION SECTION: ;dm.duke.edu. IN MX ;; ANSWER SECTION: dm.duke.edu. 3600 IN MX 10 mx.oit.duke.edu. ;; AUTHORITY SECTION: dm.duke.edu. 86400 IN NS nameserver2.mc.duke.edu. dm.duke.edu. 86400 IN NS nameserver1.mc.duke.edu. ;; Query time: 76 msec ;; SERVER: 152.16.1.12#53(152.16.1.12) ;; WHEN: Thu Sep 19 09:57:48 PDT 2024 ;; MSG SIZE rcvd: 140 Fails on IPv6: ; <<>> DiG 9.10.3-P4-Debian <<>> MX dm.duke.edu @2620:0:691:dc50::4 ;; global options: +cmd ;; connection timed out; no servers could be reached ; <<>> DiG 9.10.3-P4-Debian <<>> MX dm.duke.edu @2620:0:691:dc57::12 ;; global options: +cmd ;; connection timed out; no servers could be reached ~Seth