Different POP servers use different ways of generating UIDL values for messages, which is what the client uses to decide whether it already has a particular message. In version 1.0-tests/1.0-stable, Dovecot can emulate many of them (but not Qpopper, which uses a MD5 hash of some of the message headers). To emulate UW-IMAP set

pop3_uidl_format = %08Xu%08Xv

in dovecot.conf, rather than the default %v.%u, which is what Cyrus uses (see dovecot-example.conf).

If you're using Dovecot 0.99 or were using Qpopper (we're doing the latter!) then you'll have to grin and bear it - it'll teach your users not to abuse the POP protocol by leaving mail on the server - that's what IMAP's for ;-)

Best Wishes, Chris

Michiel van Es wrote:

Hi, we recently switched from Imap-Uw to Dovecot as a pop3 server. I was wondering why people who have the flag 'Leave messages on server' in their email client (Outlook, Outlook Expres) that they receive duplicates of their stored mail? Is it because Dovecot doesn't know that the messages has already been popped by Imap Uw or is the email client which thinks there are new messages on the server and if so..how can I avoid this behaviour?

Thanks in advance for any help.

-- --+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+- Christopher Wakelin, c.d.wakelin@reading.ac.uk IT Services Centre, The University of Reading, Tel: +44 (0)118 378 8439 Whiteknights, Reading, RG6 2AF, UK Fax: +44 (0)118 975 3094