imapc storage
=============
The imapc storage accesses a remote IMAP server as if it were a regular Dovecot
mailbox format. Dovecot can treat it as a very dummy storage or optionally a
more capable storage.
---%<-------------------------------------------------------------------------
# In-memory index files:
mail_location = imapc:
# Store index files locally:
mail_location = imapc:~/imapc
---%<-------------------------------------------------------------------------
Connection settings
-------------------
Do a regular IMAP LOGIN to imap.example.com using 'a LOGIN user@example.com
secret':
---%<-------------------------------------------------------------------------
imapc_host = imap.example.com
imapc_password = secret
imapc_port = 143
imapc_user = user@example.com
---%<-------------------------------------------------------------------------
If you want to use a master user login, set:
---%<-------------------------------------------------------------------------
imapc_master_user = masteruser
---%<-------------------------------------------------------------------------
For SSL, use either:
* ---%<----------------------------------------------------------------------
imapc_ssl = imaps
imapc_port = 993
---%<----------------------------------------------------------------------
* ---%<----------------------------------------------------------------------
imapc_ssl = starttls
imapc_port = 143
---%<----------------------------------------------------------------------
For testing you may want to disable all SSL certificate checks:
---%<-------------------------------------------------------------------------
imapc_ssl_verify = no
---%<-------------------------------------------------------------------------
You can use other SASL mechanisms besides PLAIN by specifying (the first one
advertised by IMAP server is used):
---%<-------------------------------------------------------------------------
imapc_sasl_mechanisms = external plain login
---%<-------------------------------------------------------------------------
The SASL client mechanisms are implemented in Dovecot's lib-sasl/ code. It's
possible to add more with plugins.
Other settings
--------------
imapc_cmd_timeout:
How long to wait for an IMAP command to reply before disconnecting and
retrying (default: 5 mins).
imapc_list_prefix:
Access only mailboxes under this prefix. For example
'imapc_list_prefix=INBOX/'
imapc_max_idle_time:
Send something (NOOP/DONE) to server after not sending anything for this
amount of time (default: 29 mins).
imapc_rawlog_dir:
Log all IMAP traffic input/output to this directory.
Features and workarounds
------------------------
'imapc_features' setting is a space-separated list of features and workarounds
that can be enabled.
Optimizations
-------------
rfc822.size:
Allow passing through message sizes using 'FETCH RFC822.SIZE'
fetch-headers:
Allow fetching specific message headers using 'FETCH BODY.PEEK[HEADER.FIELDS
(..)]'
fetch-bodystructure:
Allow fetching BODY and BODYSTRUCTURE from remote server. (v2.2.30+)
search:
Allow using 'SEARCH' command.
Features
--------
gmail-migration:
Enable GMail-specific migration: Use IMAP X-GM-MSGID as POP3 UIDL. Add
$GMailHaveLabels keyword to mails that have X-GM-LABELS except for \Muted (to
be used for migrating only archived emails in "All Mails"). Add
pop3_deleted_flag to mails that don't exist in POP3 server.
proxyauth:
Use Sun/Oracle IMAP-server specific PROXYAUTH command to do master user
authentication. Normally this would be done using the SASL PLAIN
authentication.
throttle:INIT:MAX:SHRINK:
When receiving [THROTTLED] response (from GMail), throttling is applied. INIT
= initial throttling msecs (default: 50 ms), afterwards each subsequent
[THROTTLED] doubles the throttling until MAX is reached (default: 16000 ms).
When [THROTTLED] is not received for a while, it's shrank again. The initial
shrinking is done after SHRINK (default: 500 ms). If [THROTTLED] is received
again within this timeout, it's doubled, otherwise both throttling and the
next shrinking timeout is shrank to 3/4.
modseq:
Access MODSEQ and HIGHESTMODSEQ (v2.2.24+)
delay-login:
Don't connect to the remote server until some command requires it. By default
the server is connected to immediately on login. (v2.2.29+)
Quota
-----
Using the "imapc" quota backend allows asking for the quota from remote IMAP
server (v2.2.30+). By default it uses GETQUOTAROOT INBOX for getting the quota.
There are also two parameters that can be used to control how the quota is
looked up:
* box=<mailbox>: Use GETQUOTAROOT <mailbox>
* root=<name>: Use GETQUOTA <name>
For example:
---%<-------------------------------------------------------------------------
plugin {
quota = imapc:root=User Quota
}
---%<-------------------------------------------------------------------------
Workarounds
-----------
zimbra-workarounds:
Fetch full message using 'BODY.PEEK[HEADER] BODY.PEEK[TEXT]' instead of just
'BODY.PEEK[]' because the header differs between these two when there are
illegal control chars or 8bit chars. This mainly caused problems with dsync,
but as of v2.2.22+ this should no longer be a problem and there's probably no
need to enable this workaround.
no-examine:
Use SELECT instead of EXAMINE even when we don't want to modify anything in
the mailbox. This is a Courier-workaround where it didn't permanently assign
UIDVALIDITY to an EXAMINEd mailbox, but assigned it for SELECTed mailbox.
fetch-msn-workarounds:
Try to ignore wrong message sequence numbers in FETCH replies whenever
possible, preferring to use the returned UID number instead.
fetch-fix-broken-mails:
If a FETCH returns 'NO' (but not 'NO [LIMIT]' or 'NO [SERVERBUG]'), assume
the mail is broken in server and just treat it as if it were an empty email.
NOTE: This is often a dangerous option! It's not safe to assume that NO means
a permanent error rather than a temporary error. This feature should be
enabled only for specific users who have been determined to be broken.
(This file was created from the wiki on 2019-06-19 12:42)
