On 17.04.24 08:43, Aki Tuomi wrote:
On 17/04/24 00:51, John Stoffel via dovecot wrote: >>>>>> "Peter" == Peter via dovecot <dovecot@dovecot.org> writes: Generally speaking you want auth to be case- sensitive, but go ahead and try it to see if it fixes the issue. Umm... not for emails you don't. Since the john@stoffel.org and JOHN@stoffel.org and JOHN@STOFFEL.ORG are all the same email address
No they aren't. The *host part* is case insensitive because the DNS is, but nothing in the RFCs suggests that the *user part* may be (generally) treated as such. That only came about when the makers of a certain, famously case insensitive OS started selling a mail server software better aligned with their habits.
(Back with SunOS, when account names automatically yielded deliverable e-mail addresses, my dpt. had a standing rule that admins would have an unprivileged account like, e.g., "bern" and a separate UID=0 account "Bern" for the admin work. Luckily, the login(1) triggered its OH, IT SEEMS THAT THIS TERMINAL SUPPORTS ONLY SINGLE CASE mode only if the username was *entirely* in uppercase, not on the first character ...)
Having that said, nothing keeps you from setting up your MTA/MDA so as to ignore case entirely (because people manually entering addresses never make typos, but erroneously slip onto <SHIFT> or <CAPSLOCK> all the time, I suppose ...), but it's a major no-no for (intermediate) MTAs.
Unfortunately some systems uppercase (or downcase) your email when sending mail to you.
In particular, websites you create an account on, apparently in fear that joe@shmoe would otherwise be able to create multiple accounts with Joe@shmoe, jOe@shmoe etc. etc.. They rarely object to plussed user addresses or single-person-owned domains that could have a catchall configured, though ...
(I *should* have tried a user part with "ß" on an upcaseing online service back when that umlaut officially *didn't have* an uppercase version ... ;-)
Kind regards,
Jochen Bern Systemingenieur
Binect GmbH