4 Sep
2019
4 Sep
'19
10:18 p.m.
It is not recommended to rely on local-part case, but it is indeed case-sensitive.
And this is to avoid such issues that postfix supports address cleanup/canonicalisation before forwarding mails to dovecot.
RFC 5321:
"Local-part = Dot-string / Quoted-string ; MAY be case-sensitive […] While the above definition for Local-part is relatively permissive, for maximum interoperability, a host that expects to receive mail SHOULD avoid defining mailboxes where the Local-part requires (or uses) the Quoted-string form or where the Local-part is case-sensitive."
And therefore “receive liberally” policy that wants to assume case-insensitivity should single-case the address IN THE COMPARISON.