I have setup Postfix and Dovecot on an Ubuntu box following these instructions.
I can see that email is being delivered to and accepted by the server, but the email is not available for retrieval via POP3. What could be missing in my configuration? It seems that email is not being properly handed off to Dovecot.
Here are what I believe are the relevant /var/log/mail.log entries for an attempt to send email from another domain (hosted by Gmail) to the domain I have setup:
Logged during SMTP connection:
postfix/smtpd[14689]: connect from mail-vb0-f50.google.com[209.85.212.50]
postfix/smtpd[14689]: Anonymous TLS connection established from mail-vb0-f50.google.com[209.85.212.50]: TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)
postfix/smtpd[14689]: 5782740ACF: client=mail-vb0-f50.google.com[209.85.212.50]
postfix/cleanup[14696]: 5782740ACF: message-id=<CAEjmKcjHnTY4yk=3QXoNrD76=04g-s9utPguTFB02Fx53GMPmw@mail.gmail.com>
postfix/qmgr[14687]: 5782740ACF: from=<my.name@sourcedomain.com>, size=1947, nrcpt=1 (queue active)
postfix/smtpd[14702]: connect from mail.destinationdomain.com[127.0.0.1]
postfix/smtpd[14702]: 2940A41AA9: client=mail.destinationdomain.com[127.0.0.1]
postfix/cleanup[14696]: 2940A41AA9: message-id=<CAEjmKcjHnTY4yk=3QXoNrD76=04g-s9utPguTFB02Fx53GMPmw@mail.gmail.com>
postfix/qmgr[14687]: 2940A41AA9: from=<my.name@sourcedomain.com>, size=2450, nrcpt=1 (queue active)
amavis[21309]: (21309-02) Passed CLEAN, [209.85.212.50] <my.name@sourcedomain.com> -> <me@destinationdomain.com>, Message-ID: <CAEjmKcjHnTY4yk=3QXoNrD76=04g-s9utPguTFB02Fx53GMPmw@mail.gmail.com>, mail_id: W52ZB8FAAA+8, Hits: -0.101, size: 1946, queued_as: 2940A41AA9, dkim_id=@sourcedomain.com, 784 ms
postfix/smtpd[14702]: disconnect from mail.destinationdomain.com[127.0.0.1]
postfix/smtp[14698]: 5782740ACF: to=<me@destinationdomain.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=1.1, delays=0.29/0.01/0/0.79, dsn=2.0.0, status=sent (250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 2940A41AA9)
postfix/qmgr[14687]: 5782740ACF: removed
dovecot: lda(me@destinationdomain.com): msgid=<CAEjmKcjHnTY4yk=3QXoNrD76=04g-s9utPguTFB02Fx53GMPmw@mail.gmail.com>: saved mail to INBOX
postfix/pipe[14703]: 2940A41AA9: to=<me@destinationdomain.com>, relay=dovecot, delay=0.08, delays=0.02/0.02/0/0.04, dsn=2.0.0, status=sent (delivered via dovecot service)
postfix/qmgr[14687]: 2940A41AA9: removed
Logged during POP3 retrieval attempts:
dovecot: pop3-login: Login: user=<me@destinationdomain.com>, method=PLAIN, rip=209.85.220.135, lip=10.195.83.10, mpid=14706
dovecot: pop3(me@destinationdomain.com): Disconnected: Logged out top=0/0, retr=1/2557, del=1/1, size=2540
postfix/smtpd[14689]: disconnect from mail-vb0-f50.google.com[209.85.212.50]
dovecot: pop3-login: Login: user=<me@destinationdomain.com>, method=PLAIN, rip=209.85.212.31, lip=10.195.83.10, mpid=14708
dovecot: pop3(me@destinationdomain.com): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Best Answer
So.. the seemingly obvious strategy here is to try to break down your problem from "a Postfix and Dovecot problem" to "a Postfix problem" or "a Dovecot problem."
When incoming mail is accepted for delivery by Postfix is it being delivered properly to a local mailbox? Can you access it on the server using a local mail client (e.g. /usr/bin/mailx or /usr/ucb/Mail?)
If you confirm that Postfix is working properly to receive incoming mail and handing mail off properly for local delivery, then look at where Dovecot is checking to find user mail -- is it possible it's expecting mailboxes to live somewhere other than where you are putting them? (e.g. system mail spool directory with a different name than expected, or expecting to find them in user home directories)?