Hi David
I believe RFC822 email addresses are case-insensitive, and (in some
RFC 2821, Page 13, 1st paragraph: "The local-part of a mailbox MUST BE treated as case sensitive. Therefore, SMTP implementations MUST take care to preserve the case of mailbox local-parts. Mailbox domains are not case sensitive. In particular, for some hosts the user "smith" is different from the user "Smith". However, exploiting the case sensitivity of mailbox local-parts impedes interoperability and is discouraged." (http://tools.ietf.org/html/rfc2821#section-2.4)
cases, especially ones where there's just a mail server) it's entirely possible that people remember their account names with some capital letters that aren't in user db. (System knows you as "mrsmithy@mail.domain", while the user may remember the account as "MrSmithy@mail.domain" or "MrsMithy@mail.domain"...). Also, people with
I just want login names to be case sensitive but not email addresses, and in spite of being treated as case insensitive email addresses should retain their case, just like defined and suggested in the RFC.
This reduces support calls because it's con-formant and we have a clear policy: Usernames are always lower case, non-email addresses, the same simple and short name for all our services. There is nothing easier than this. We use this since 17 years and it works without confusion. If a user now spots that suddendly any capitalization of usernames is working when logging in to the webmail, how can I explain that this doesn't work with other services like FTP?
smartphones may not notice that the phone "helpfully" uppercased the first letter of a lowercase user name. Forcing case reduces support calls, which is always a good thing. That's why email addresses should be allowed containing capitalizations. On smartphone people tend to use MUAs and there the username is saved and not entered each and every time, so for the username this is less true, I think.
Back to dovecot: Using LDA as a transport for the dovecot store, it used to work perfectly (with dovecot 1.x). It's just LMTP that spits, because it looks up the local part in the userdb, which is PAM in our case. I won't change PAM to act case insensitive: I'm not in the position to change a common sense in the computing world as it always was. It's enough Microsoft did that and probably just because of that we're having this discussion here...
However, it's maybe best to lowercase the local part in the exim lmtp-transport and leave dovecot's LMTP in peace.
Best regards, Adrian.