Sorry: not Amazon DNS – 10.204.109.209 is a BIND server in our network we've setup to work with our global VPN/DNS. BUT the strange thing is that the domain lookup works with musl-1.1.24 while with some musl-1.2.x just quits with an error. a comparison with the docker runs and `sudo tcpdump -v -i docker0 udp port 53 or tcp port 53` did not bring up any diffs except the list of A records returned is in a different order (which i think is completely normal). the order of requests is the same tcpdump from working version: > bind-us-east-1a.XXXXXXXXXXXXXX.domain > 172.17.0.3.45501: 18685 9/13/8 slack.com. A 3.95.117.96, slack.com. A 34.231.24.224, slack.com. A 54.163.235.119, slack.com. A 54.147.59.169, slack.com. A 34.193.255.5, slack.com. A 34.204.109.226, slack.com. A 34.225.62.185, slack.com. A 34.203.97.10, slack.com. A 54.92.199.186 (510) tcpdump from non-working version: > bind-us-east-1a.XXXXXXXXXXXXXX.domain > 172.17.0.3.59951: 49211 9/13/8 slack.com. A 34.225.62.185, slack.com. A 54.163.235.119, slack.com. A 34.231.24.224, slack.com. A 54.147.59.169, slack.com. A 34.193.255.5, slack.com. A 34.204.109.226, slack.com. A 54.92.199.186, slack.com. A 3.95.117.96, slack.com. A 34.203.97.10 (510) Complete log: 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49211+ A? slack.com. (27) 18:56:19.990087 IP (tos 0x0, ttl 64, id 10210, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:20.154990 IP (tos 0x0, ttl 250, id 17825, offset 0, flags [none], proto UDP (17), length 538) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49211 9/13/8 slack.com. A 34.225.62.185, slack.com. A 54.163.235.119, slack.com. A 34.231.24.224, slack.com. A 54.147.59.169, slack.com. A 34.193.255.5, slack.com. A 34.204.109.226, slack.com. A 54.92.199.186, slack.com. A 3.95.117.96, slack.com. A 34.203.97.10 (510) 18:56:20.241377 IP (tos 0x0, ttl 250, id 17846, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:20.241501 IP (tos 0x0, ttl 64, id 10233, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:20.401765 IP (tos 0x0, ttl 250, id 17879, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:20.401831 IP (tos 0x0, ttl 64, id 10247, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:20.563915 IP (tos 0x0, ttl 250, id 17906, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:20.563946 IP (tos 0x0, ttl 64, id 10300, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:20.801072 IP (tos 0x0, ttl 250, id 17915, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:20.801187 IP (tos 0x0, ttl 64, id 10392, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:20.961903 IP (tos 0x0, ttl 250, id 17948, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:22.492127 IP (tos 0x0, ttl 64, id 10410, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:22.745884 IP (tos 0x0, ttl 250, id 18135, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:22.745930 IP (tos 0x0, ttl 64, id 10492, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:22.906904 IP (tos 0x0, ttl 250, id 18171, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:22.906941 IP (tos 0x0, ttl 64, id 10548, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:23.067742 IP (tos 0x0, ttl 250, id 18209, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:23.067773 IP (tos 0x0, ttl 64, id 10559, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:23.228046 IP (tos 0x0, ttl 250, id 18244, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:23.228083 IP (tos 0x0, ttl 64, id 10598, offset 0, flags [DF], proto UDP (17), length 55) 172.17.0.3.59951 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 49334+ AAAA? slack.com. (27) 18:56:23.388598 IP (tos 0x0, ttl 250, id 18274, offset 0, flags [none], proto UDP (17), length 55) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.59951: 49334 ServFail 0/0/0 (27) 18:56:24.998168 IP (tos 0x0, ttl 64, id 10759, offset 0, flags [none], proto UDP (17), length 55) 172.17.0.3.55720 > bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain: 2282+ ANY? slack.com. (27) 18:56:25.199844 IP (tos 0x0, ttl 250, id 18505, offset 0, flags [none], proto UDP (17), length 538) bind-us-east-1a.XXXXXXXXXXXXXXXXXXXXXXXXXx.domain > 172.17.0.3.55720: 2282 9/13/8 slack.com. A 34.231.24.224, slack.com. A 34.193.255.5, slack.com. A 54.163.235.119, slack.com. A 54.92.199.186, slack.com. A 54.147.59.169, slack.com. A 3.95.117.96, slack.com. A 34.225.62.185, slack.com. A 34.204.109.226, slack.com. A 34.203.97.10 (510) Thanks for looking into! Greetings, Markus