Re: Uppercase username emails are rejected

On 7/04/24 02:34, lua8ds--- via dovecot wrote:

When a sender writes my email address with my username uppercase, e.g. USERNAME@name.com, in the to: field of their MUA, my mail server rejects that email. /var/log/mail.log prints:

<USERNAME@redacted.com>: host mail.redacted.com[private/dovecot-lmtp] said: 550 5.1.1
>    <USERNAME@redacted.com> User doesn't exist: USERNAME@redacted.com (in reply to RCPT TO
>    command)

In the manual, I found that:

auth_username_format

auth_username_format is for the authentication backend and has nothing to do with receiving mail. You want to change the args line under userdb, add an "L" modifier to username_format, so something like:

args = username_format=%Ln ...

Alternatively you can probably configure your MTA to lowercase the username before it passes the message off to dovecot.

Peter