Hi, We are running Cyrus-imapd-2.1.11 with sieve and duplicate delivery suppression. One of our users complained that they had not been receiving mail. It appears that this is because he has set up a sieve script with a redirect rule which redirects all his mail to himself (his own email address).
As far as I can tell, his mail is initially delivered to his Inbox, at which point lmtpd redirects the mail back via the MTA to his email address. The redirected mail is delivered a second time, at which point it appears that the mail is suppressed by Cyrus' duplicate delivery suppression. I have seen a few references to this behaviour on the list from a while back, but I'm not sure if this problem has been addressed in 2.1.11 or later. When a redirect rule redirects mail to the same mailbox in this way, will this always result in mail being silently discarded? Would this problem be solved by disabling duplicate delivery suppression? I am slightly confused by the fact that lmtpd is not actually logging that it has suppressed the message when this occurs. Yet the messages never appear in the user's Inbox. Obviously the user's sieve script is broken and I would expect it to produce a mail loop, which our MTA should handle. But it is very likely that other users will inadvertently redirect mail to themselves, and if this is going to cause mail to be lost we may have to disable duplicate delivery suppression. -- Stephen Grier Systems Developer Computing Services Queen Mary, University of London
