Using dovecot 1.2beta (but earlier versions should behave similarly) we have a problem in conjunction with empty To: headers and the RT request tracker.
RT sends mail out using Bcc: and no To: header at all. To make some mailers happy one can configure to send a dummy To: header, which we do.
Our To header looks like: To: "AdminCc of rt Ticket #123456":;
The message_address_parse function called with the TRUE flag (triggers add_fixed_address) in dovecot changes that to To: AdminCc of rt Ticket #123456: MISSING_MAILBOX@MISSING_DOMAIN ;
and then at least alpine does use that invalid address as Cc: address when replying. If the mail is stored in a local folder, i.e. does not get fetched via IMAP then the To: line is displayed as is and a reply does not result in an errorneous Cc:
This behaviour is at least inconsistent from a user point of view. Is there some advice other than change the RT mail header generation?
(other mailers seem to copy the To: line unaltered which results in an invalid address as well, therefore I admit that the real problem is with RT)
Wolfgang Friebel Deutsches Elektronen-Synchrotron DESY Phone/Fax: +49 33762 77372/216 Platanenallee 6 Mail: Wolfgang.Friebel AT desy.de D-15738 Zeuthen Germany