dns names starting with numbers are ignored
$ drill acme-staging-v02.api.letsencrypt.org
[ ... ]
56a5f4b0bc8146689ec3e272c43525f9.pacloudflare.com. 300 IN A 172.65.46.172
rejected by https://gitlab.alpinelinux.org/alpine/awall/-/blob/master/awall/family.lua#L10 but according to https://serverfault.com/questions/638260/is-it-valid-for-a-hostname-to-start-with-a-digit this was made valid by RFC 1123