DNS lookup fails

[Undearius]

After modifying config.yaml to point to my matrix server domain name and adding the registration file to synapse, running the docker results in this error
[ERROR] Failed to connect to homeserver: failed to ensure registered: request error: Post "https://<my_domain>/_matrix/client/r0/register?user_id=%40whatsappbot%3A<my_domain>": dial tcp: lookup <my_domain> on [::1]:53: dial udp [::1]:53: connect: cannot assign requested address. Retrying in 10 seconds...

[::1]:53 is telling me it's trying to do a lookup for an IPv6 address when everything is configured with IPv4 addresses.

Is it possible that Golang defaults are kicking in with defaultNS = []string{"127.0.0.1:53", "[::1]:53"
https://github.com/golang/go/blob/master/src/net/dnsconfig_unix.go

The container's /etc/resolv.conf file only has these two entries
nameserver 1.1.1.1
nameserver 8.8.8.8

[tulir]

This doesn't sound related to the bridge. There's nothing special related to DNS in the bridge nor in the docker image.

[Undearius]

Seems to be caused by this golang/go#25321

[Undearius]

May have been cause by this golang/go#45024

Either way, after updating the docker container, this is working now.