On 17/04/2024 12:42 EEST Marc via dovecot dovecot@dovecot.org wrote: No they aren't. The *host part* is case insensitive because the DNS is, Indeed. Letsencrypt is utilizing this characteristic, they query the same hostname every time with different randomized(?) capitalizations. I have no idea what the logics behind this is. Preventing this from showing in logs? Preventing rate limiters to be triggered? No idea why they do this. >, but erroneously slip onto <SHIFT> or <CAPSLOCK> all the time, I suppose ...), :D _______________________________________________ dovecot mailing list -- dovecot@dovecot.org To unsubscribe send an email to dovecot-leave@dovecot.org This is a DNS hardening thing to make it harder to spoof replies. DNS name comparison is still case insensitive. Aki