Dovecot
From apnsGuide
Contents |
Overview
The Dovecot category encompasses both IMAP and POP3 e-mail connectivity. For protocol-specific issues, please refer to the corresponding Wiki section.
IMAP vs POP3
POP3 is a limited protocol designed during the days of dial-up, limited Internet connectivity, and limited space. POP3 generally downloads messages from the server and immediately removes from the server to save on space. As a consequence of this behavior, messages are not accessible through webmail or another e-mail client.
IMAP is a more robust protocol that keeps messages on the server and only downloads the subject lines. Once you access an e-mail in your inbox, then the e-mail client makes another request to retrieve the body of the message. IMAP's selective fetching capabilities carry one downside: you can't view the e-mail unless you are connected to the server. IMAP additionally allows for multiple mailboxes, configurable within the e-mail client, and multiple clients to simultaneously connect and view a single mailbox.
Usage
Logging In
The login mechanism is shared between FTP, SSH, apnscp esprit, SMTP, and IMAP/POP3. FTP, SSH, and e-mail use the same login form of
user@domain. If your client does not properly interpret @ as part of the login, then you may swap @ with #. Logins should always be provided in lowercase. Unless you have made custom modifications to your DNS records the hostname/server name will always be your domain name. You may use any secondary domain attached to your hosting account listed in Multiple Domain Manager.
Your incoming/outgoing mail server is simply your domain name. Generally we provide the mail server name in the form mail.domain, but specifying just the domain name is adequate.
You may use either your primary domain or any secondary domain added through Multiple Domain Manager in the login. If apnscp.com is a secondary domain for apisnetworks.com, then msaladna@apisnetworks.com and msaladna@apnscp.com would both be valid logins for the user msaladna.
Setup in Thunderbird
Tools -> Account Settings -> Add Account to bring up the wizard. Select "Email Account" and enter your real name and e-mail address to be used with the new account. Based upon your preferences, either select POP or IMAP. General login information is provided above.
Setup in Outlook
Setup in Mail.app
Who has access to a Mac and wants to do this? msaladna
Questions
What IMAP/POP3 daemon is used?
Dovecot 1.0 is used on the servers. We chose Dovecot primarily for its IDLE, epoll, inotify, and Maildir support backed by a secure, well-maintained track record.
Where is mail located on the server?
Mail is stored under /home/user/Mail/ for each user on the server. Each message resides in its own file under /home/user/Mail/cur/. Messages that have arrived since the last user login are stored under /home/user/Mail/new/. After logging in, messages are moved from new/ to cur/.
Is concurrent e-mail access possible?
Yes, concurrent e-mail access with multiple e-mail clients will work without incident. Concurrency is one of the many attributes of the Maildir mail storage format.
Troubleshooting
Mail retrieval no longer works/Blank Webmail login/"* BYE Internal error occurred" †
In all recorded cases this has been caused by the user going over quota. To confirm this, login to the control panel and visit Quota Tracker. Disk quotas may be adjusted under Manage Users and Mailboxes. You may need to close your e-mail client and reopen it in order for the changes to take effect.
In certain cases the internal cache file used by Dovecot may become corrupted as a result of a user going over quota. If you have adjusted the user's quota and are still experiencing problems, then you will need to delete the internal cache files. These are located under /home/<user>/Mail/ and named dovecot.index.log and dovecot.index.cache. After removing both files e-mail access should return to normal.
Note: if the user had remained over quota for over 5 days the server automatically disables the account to prevent further pile-up. Visit Mailbox Routes to re-enable the disabled account.
†: "* BYE Internal error occurred" as reported by users:
ERROR: IMAP server closed the connection.
Query: FETCH 20771:20772,20924 (INTERNALDATE FLAGS BODY.PEEK[HEADER.FIELDS (From Content-Type X-Priority Subject Importance Priority)])
Server responded:* BYE Internal error occurred. Refer to server log for more information. [2008-01-23 16:27:46]
Variation of the same error:
ERROR: IMAP server closed the connection.
Query: FETCH 20982 (FLAGS BODYSTRUCTURE)
Server responded:* BYE Internal error occurred. Refer to server log for more information. [2008-01-23 16:30:41]
