/etc/imapd.conf
is the configuration file for the Cyrus IMAP server. It defines
local parameters for IMAP.
Each line of the /etc/imapd.conf file has the form
option: value
where option is the name of the configuration option being set
and value is the value that the configuration option is being
set to.
Blank lines and lines beginning with ``#'' are ignored.
For boolean and enumerated options, the values ``yes'', ``on'', ``t'',
``true'' and ``1'' turn the option on, the values ``no'', ``off'',
``f'', ``false'' and ``0'' turn the option off.
FIELD DESCRIPTIONS
The sections below detail options that can be placed in the
/etc/imapd.conf file, and show each option's default value.
Some options have no default value, these are listed with
``<no default>''. Some options default to the empty string, these
are listed with ``<none>''. It is also possible to override options by
specifying them as <service_id>_<optionname>. One example is ``lmtp_admins'',
which overrides ``admins'' just for the lmtp service. The <service_id> is the
one you specified in the /etc/cyrus.conf file.
admins: <empty string>
The list of userids with administrative rights. Separate each userid
with a space. Sites using Kerberos authentication may use
separate "admin" instances.
Note that accounts used by users should not be administrators.
Administrative accounts should not receive mail. That is, if user
"jbRo" is a user reading mail, he should not also be in the admins line.
Some problems may occur otherwise, most notably the ability of
administrators to create top-level mailboxes visible to users,
but not writable by users.
afspts_localrealms: <none>
The list of realms which are to be treated as local, and thus stripped
during identifier canoicalization (for the AFSPTS ptloader module).
This is different from loginrealms in that it occurs later in the
authorization process (as the user id is canonified for PTS lookup)
afspts_mycell: <none>
Cell to use for AFS PTS lookups. Defaults to the local cell.
allowallsubscribe: 0
Allow subscription to nonexistent mailboxes. This option is
typically used on backend servers in a Murder so that users can
subscribe to mailboxes that don't reside on their "home" server.
This option can also be used as a workaround for IMAP clients which
don't play well with nonexistent or unselectable mailboxes (eg.
Microsoft Outlook).
allowanonymouslogin: 0
Permit logins by the user "anonymous" using any password. Also
allows use of the SASL ANONYMOUS mechanism.
allowapop: 1
Allow use of the POP3 APOP authentication command.
Note that this command requires that SASL is compiled with APOP
support, that the plaintext passwords are available in a SASL auxprop
backend (eg. sasldb), and that the system can provide enough entropy
(eg. from /dev/urandom) to create a challenge in the banner.
allownewnews: 0
Allow use of the NNTP NEWNEWS command.
Note that this is a very expensive command and should only be
enabled when absolutely necessary.
allowplaintext: 1
Allow the use of cleartext passwords on the wire.
To disallow the use of plaintext passwords for authentication, you can
set ``allowplaintext: no'' in imapd.conf. This will still allow PLAIN
under TLS, but IMAP LOGIN commands will now fail.
If you only list plaintext authentication mechanisms in ``sasl_mech_list''
and set ``allowplaintext: no'', only users on encrypted sessions (TLS or
SSL) will be able to authenticate. On the other hand, if you list no
plaintext authentication options in ``sasl_mech_list'',
``allowplaintext: yes'' would have no effect.
allowusermoves: 0
Allow moving user accounts (with associated meta-data) via RENAME
or XFER.
Note that measures should be taken to make sure that the user being
moved is not logged in, and can not login during the move. Failure
to do so may result in the user's meta-data (seen state,
subscriptions, etc) being corrupted or out of date.
altnamespace: 0
Use the alternate IMAP namespace, where personal folders reside at the
same level in the hierarchy as INBOX.
This option ONLY applies where interaction takes place with the
client/user. Currently this is limited to the IMAP protocol (imapd)
and Sieve scripts (lmtpd). This option does NOT apply to admin tools
such as cyradm (admins ONLY), reconstruct, quota, etc., NOR does it
affect LMTP delivery of messages directly to mailboxes via
plus-addressing.
annotation_db: skiplist
The cyrusdb backend to use for mailbox annotations.
Allowed values: berkeley, berkeley-hash, skiplist
auth_mech: unix
The authorization mechanism to use.
Allowed values: unix, pts, krb, krb5
autocreatequota: 0
If nonzero, normal users may create their own IMAP accounts by
creating the mailbox INBOX. The user's quota is set to the value
if it is positive, otherwise the user has unlimited quota.
berkeley_cachesize: 512
Size (in kilobytes) of the shared memory buffer pool (cache) used
by the berkeley environment. The minimum allowed value is 20. The
maximum allowed value is 4194303 (4GB).
berkeley_locks_max: 50000
Maximum number of locks to be held or requested in the berkeley
environment.
berkeley_txns_max: 100
Maximum number of transactions to be supported in the berkeley
environment.
client_timeout: 10
Number of seconds to wait before returning a timeout failure when
performing a client connection (e.g. in a murder enviornment)
configdirectory: <none>
The pathname of the IMAP configuration directory. This field is
required.
debug_command: <none>
Debug command to be used by processes started with -D option. The string
is a C format string that gets 3 options: the first is the name of the
executable (without path). The second is the pid (integer) and the third
is the service ID. Example: /usr/local/bin/gdb /usr/cyrus/bin/%s %d
defaultacl: anyone lrs
The Access Control List (ACL) placed on a newly-created (non-user)
mailbox that does not have a parent mailbox.
defaultdomain: <none>
The default domain for virtual domain support. Note that this domain
is stripped from the email-address transmitted using LMTP, but it
is not stripped from usernames at login-time. For imapd/pop3d,
"user" and "user@defaultdomain" specify two different users.
Please check install-virtdomains.html for details.
defaultpartition: default
The partition name used by default for new mailboxes.
deleteright: c
The right that a user needs to delete a mailbox.
duplicate_db: berkeley-nosync
The cyrusdb backend to use for the duplicate delivery suppression
and sieve.
If enabled, lmtpd will suppress delivery of a message to a mailbox if
a message with the same message-id (or resent-message-id) is recorded
as having already been delivered to the mailbox. Records the mailbox
and message-id/resent-message-id of all successful deliveries.
foolstupidclients: 0
If enabled, only list the personal namespace when a LIST "*" is performed.
(it changes the request to a LIST "INBOX*"
force_sasl_client_mech: <none>
Force preference of a given SASL mechanism for client side operations
(e.g. murder enviornments). This is separate from (and overridden by)
the ability to use the <host shortname>_mechs option to set prefered
mechanisms for a specific host
fulldirhash: 0
If enabled, uses an improved directory hashing scheme which hashes
the entire username instead of using just the first letter. This
changes hash algorithm used for quota and user directories and if
hashimapspool is enabled, the entire mail spool.
Note that this option can NOT be changed on a live system. The
server must be quiesced and then the directories moved with the
rehash utility.
hashimapspool: 0
If enabled, the partitions will also be hashed, in addition to the
hashing done on configuration directories. This is recommended if
one partition has a very bushy mailbox tree.
hostname_mechs: <none>
Force a particuar list of SASL mechanisms to be used when authenticating
to the backend server hostname (where hostname is the short hostname of
the server in question). If it is not specified it will query the server
for available mechanisms and pick one to use. - Cyrus Murder
hostname_password: <none>
The password to use for authentication to the backend server hostname
(where hostname is the short hostname of the server) - Cyrus Murder
idlemethod: %IDLE%
The idle backend to use for IDLE command.
Allowed values: no, poll, idled
idlesocket: {configdirectory}/socket/idle
Unix domain socket that idled listens on.
ignorereference: 0
For backwards compatibility with Cyrus 1.5.10 and earlier -- ignore
the reference argument in LIST or LSUB commands.
imapidlepoll: 60
The interval (in seconds) for polling the mailbox for changes while
running the IDLE command. This option is used when idled can not
be contacted or when polling is used exclusively. The minimum
value is 1. A value of 0 will disable polling (and disable IDLE if
polling is the only method available).
imapidresponse: 1
If enabled, the server responds to an ID command with a parameter
list containing: version, vendor, support-url, os, os-version,
command, arguments, environment. Otherwise the server returns NIL.
imapmagicplus: 0
Only list a restricted set of mailboxes via IMAP by using
userid+namespace syntax as the authentication/authorization id.
Using userid+ (with an empty namespace) will list only subscribed
mailboxes.
implicit_owner_rights: lca
The implicit Access Control List (ACL) for the owner of a mailbox.
@include: <none>
Directive which includes the specified file as part of the
configuration. If the path to the file is not absolute, CYRUS_PATH
is prepended.
ldap_authz: <none>
SASL authorization ID for the LDAP server
ldap_base: <empty string>
Contains the LDAP base dn for the LDAP ptloader module
ldap_bind_dn: <none>
Bind DN for the connection to the LDAP server (simple bind).
Do not use for anonymous simple binds
ldap_deref: never
Specify how aliases dereferencing is handled during search.
Allowed values: search, find, always, never
ldap_filter: (uid=%u)
Specify a filter that searches user identifiers. The following tokens can be
used in the filter string:
%% = %
%u = user
%U = user portion of %u (%U = test when %u = test@domain.tld)
%d = domain portion of %u if available (%d = domain.tld when %u =
%test@domain.tld), otherwise same as %r
%D = user dn. (use when ldap_member_method: filter)
%1-9 = domain tokens (%1 = tld, %2 = domain when %d = domain.tld)
ldap_filter is not used when ldap_sasl is enabled.
ldap_group_base: <empty string>
LDAP base dn for ldap_group_filter.
ldap_group_filter: (cn=%u)
Specify a filter that searches for group identifiers.
See ldap_filter for more options.
ldap_group_scope: sub
Specify search scope for ldap_group_filter.
Allowed values: sub, one, base
ldap_id: <none>
SASL authentication ID for the LDAP server
ldap_mech: <none>
SASL mechanism for LDAP authentication
ldap_member_attribute: <none>
See ldap_member_method.
ldap_member_base: <empty string>
LDAP base dn for ldap_member_filter.
ldap_member_filter: (member=%D)
Specify a filter for "ldap_member_method: filter".
See ldap_filter for more options.
ldap_member_method: attribute
Specify a group method. The "attribute" method retrieves groups from
a multi-valued attribute specified in ldap_member_attribute.
The "filter" method uses a filter, specified by ldap_member_filter, to find
groups; ldap_member_attribute is a single-value attribute group name.
Allowed values: attribute, filter
ldap_member_scope: sub
Specify search scope for ldap_member_filter.
Allowed values: sub, one, base
ldap_password: <none>
Password for the connection to the LDAP server (SASL and simple bind).
Do not use for anonymous simple binds
ldap_realm: <none>
SASL realm for LDAP authentication
ldap_referrals: 0
Specify whether or not the client should follow referrals.
ldap_restart: 1
Specify whether or not LDAP I/O operations are automatically restarted
if they abort prematurely.
Specify a number of entries for a search request to return.
ldap_start_tls: 0
Use StartTLS extended operation. Do not use ldaps: ldap_uri when
this option is enabled.
ldap_time_limit: 5
Specify a number of seconds for a search request to complete.
ldap_timeout: 5
Specify a number of seconds a search can take before timing out.
ldap_tls_cacert_dir: <none>
Path to directory with CA (Certificate Authority) certificates.
ldap_tls_cacert_file: <none>
File containing CA (Certificate Authority) certificate(s).
ldap_tls_cert: <none>
File containing the client certificate.
ldap_tls_check_peer: 0
Require and verify server certificate. If this option is yes,
you must specify ldap_tls_cacert_file or ldap_tls_cacert_dir.
ldap_tls_ciphers: <none>
List of SSL/TLS ciphers to allow. The format of the string is
described in ciphers(1).
ldap_tls_key: <none>
File containing the private client key.
ldap_uri: <none>
Contains a list of the URLs of all the LDAP servers when using the
LDAP PTS module.
ldap_version: 3
Specify the LDAP protocol version. If ldap_start_tls and/or
ldap_use_sasl are enabled, ldap_version will be automatiacally
set to 3.
lmtp_downcase_rcpt: 0
If enabled, lmtpd will convert the recipient address to lowercase
(up to a '+' character, if present).
lmtp_over_quota_perm_failure: 0
If enabled, lmtpd returns a permanent failure code when a user's
mailbox is over quota. By default, the failure is temporary,
causing the MTA to queue the message and retry later.
lmtpsocket: {configdirectory}/socket/lmtp
Unix domain socket that lmtpd listens on, used by deliver(8). This should
match the path specified in cyrus.conf(5).
loginrealms: <empty string>
The list of remote realms whose users may authenticate using cross-realm
authentication identifiers. Seperate each realm name by a space. (A
cross-realm identity is considered any identity returned by SASL
with an "@" in it.) Note that to support multiple virtual domains
on the same interface/IP, you need to list them all as loginreals.
If you don't list them here, your users probably won't be able to
log in.
loginuseacl: 0
If enabled, any authentication identity which has a rights on a
user's INBOX may log in as that user.
logtimestamps: 0
Include notations in the protocol telemetry logs indicating the number of
seconds since the last command or response.
mailnotifier: <none>
Notifyd(8) method to use for "MAIL" notifications. If not set, "MAIL"
notifications are disabled.
maxmessagesize: 0
Maximum incoming LMTP message size. If non-zero, lmtpd will reject
messages larger than maxmessagesize bytes. If set to 0, this
will allow messages of any size (the default).
If enabled, lmtpd changes 8-bit characters to `X'. Also see reject8bit.
(A proper soultion to non-ASCII characters in headers is offered by
RFC 2047 and its predecessors.)
mupdate_connections_max: 128
The max number of connections that a mupdate process will allow, this
is related to the number of file descriptors in the mupdate process.
Beyond this number connections will be immedately issued a BYE response.
mupdate_authname: <none>
The SASL username (Authentication Name) to use when authenticating to the
mupdate server (if needed).
mupdate_password: <none>
The SASL password (if needed) to use when authenticating to the
mupdate server.
mupdate_port: 3905
The port of the mupdate server for the Cyrus Murder
mupdate_realm: <none>
The SASL realm (if needed) to use when authenticating to the mupdate
server.
mupdate_retry_delay: 20
The base time to wait between connection retries to the mupdate server.
mupdate_server: <none>
The mupdate server for the Cyrus Murder
mupdate_workers_start: 5
The number of mupdate worker threads to start
mupdate_workers_minspare: 2
The minimum number of idle mupdate worker threads
mupdate_workers_maxspare: 10
The maximum number of idle mupdate worker threads
mupdate_workers_max: 50
The maximum number of mupdate worker threads (overall)
mupdate_username: <empty string>
The SASL username (Authorization Name) to use when authenticating to
the mupdate server
If enabled at compile time, this specifies a URL to reply when
Netscape asks the server where the mail administration HTTP server
is. The default is a site at CMU with a hopefully informative
message; administrators should set this to a local resource with
some information of greater use.
newsmaster: news
Userid that is used for checking access controls when executing
Usenet control messages. For instance, to allow articles to be
automatically deleted by cancel messages, give the "news" user
the 'd' right on the desired mailboxes. To allow newsgroups to be
automatically created, deleted and renamed by the corresponding
control messages, give the "news" user the 'c' right on the desired
mailbox hierarchies.
newspeer: <none>
A list of whitespace-separated news server specifications to which
articles should be fed. Each server specification is a string of
the form [user[:pass]@]host[:port][/wildmat] where 'host' is the fully
qualified hostname of the server, 'port' is the port on which the
server is listening, 'user' and 'pass' are the authentication
credentials and 'wildmat' is a pattern that specifies which groups
should be fed. If no 'port' is specified, port 119 is used. If
no 'wildmat' is specified, all groups are fed. If 'user' is specified
(even if empty), then the NNTP POST command will be used to feed
the article to the server, otherwise the IHAVE command will be
used.
A '@' may be used in place of '!' in the wildmat to prevent feeding
articles cross-posted to the given group, otherwise cross-posted
articles are fed if any part of the wildmat matches. For example,
the string "peer.example.com:*,!control.*,@local.*" would feed all
groups except control messages and local groups to
peer.example.com. In the case of cross-posting to local groups,
these articles would not be fed.
newspostuser: <none>
Userid used to deliver usenet articles to newsgroup folders
(usually via lmtp2nntp). For example, if set to "post", email sent
to "post+comp.mail.imap" would be delivered to the "comp.mail.imap"
folder.
When set, the Cyrus NNTP server will add a To: header to each
incoming usenet article. This To: header will contain email
delivery addresses corresponding to each newsgroup in the
Newsgroups: header. By default, a To: header is not
added to usenet articles.
newsprefix: <none>
Prefix to be prepended to newsgroup names to make the corresponding
IMAP mailbox names.
notifysocket: {configdirectory}/socket/notify
Unix domain socket that the mail notification daemon listens on.
partition-name: <none>
The pathname of the partition name. At least one field, for the
partition named in the defaultpartition option, is required.
For example, if the value of the defaultpartion option is
default, then the partition-default field is required.
plaintextloginpause: 0
Number of seconds to pause after a successful plaintext login. For
systems that support strong authentication, this permits users to
perceive a cost of using plaintext passwords. (This does not
affect the use of PLAIN in SASL authentications.)
plaintextloginalert: <none>
Message to send to client after a successful plaintext login.
popexpiretime: -1
The number of days advertised as being the minimum a message may be
left on the POP server before it is deleted (via the CAPA command,
defined in the POP3 Extension Mechanism, which some clients may
support). "NEVER", the default, may be specified with a negative
number. The Cyrus POP3 server never deletes mail, no matter what
the value of this parameter is. However, if a site implements a
less liberal policy, it needs to change this parameter
accordingly.
popminpoll: 0
Set the minimum amount of time the server forces users to wait
between successive POP logins, in minutes.
poppollpadding: 1
Create a softer minimum poll restriction. Allows poppollpadding
connections before the minpoll restriction is triggered. Additionally,
one padding entry is recovered every popminpoll minutes.
This allows for the occasional polling rate faster than popminpoll,
(i.e. for clients that require a send/recieve to send mail) but still
enforces the rate long-term. Default is 1 (disabled).
The easiest way to think of it is a queue of past connections, with one
slot being filled for every connection, and one slot being cleared
every popminpoll minutes. When the queue is full, the user
will not be able to check mail again until a slot is cleared. If the
user waits a sufficent amount of time, they will get back many or all
of the slots.
poptimeout: 10
Set the length of the POP server's inactivity autologout timer,
in minutes. The minimum value is 10, the default.
popuseacl: 0
Enforce IMAP ACLs in the pop server. Due to the nature of the POP3
protocol, the only rights which are used by the pop server are 'r'
and 'd' for the owner of the mailbox. The 'r' right allows the
user to open the mailbox and list/retrieve messages. The 'd' right
allows the user to delete messages.
postmaster: postmaster
Username that is used as the 'From' address in rejection MDNs produced
by sieve.
postuser: <empty string>
Userid used to deliver messages to shared folders. For example, if
set to "bb", email sent to "bb+shared.blah" would be delivered to
the "shared.blah" folder. By default, an email address of
"+shared.blah" would be used.
proxy_authname: proxy
The authentication name to use when authenticating to a backend server
in the Cyrus Murder.
proxy_password: <none>
The default password to use when authenticating to a backend server
in the Cyrus Murder. May be overridden on a host-specific basis using
the hostname_password option.
proxy_realm: <none>
The authentication realm to use when authenticating to a backend server
in the Cyrus Murder
proxyd_allow_status_referral: 0
Set to true to allow proxyd to issue referrals to clients that support it
when answering the STATUS command. This is disabled by default since
some clients issue many STATUS commands in a row, and do not cache the
connections that these referrals would cause, thus resulting in a higher
authentication load on the respective backend server.
proxyd_disable_mailbox_referrals: 0
Set to true to disable the use of mailbox-referrals on the
proxy servers.
proxyservers: <none>
A list of users and groups that are allowed to proxy for other
users, seperated by spaces. Any user listed in this will be
allowed to login for any other user: use with caution.
pts_module: afskrb
The PTS module to use.
Allowed values: afskrb, ldap
ptloader_sock: <none>
Unix domain socket that ptloader listens on.
(defaults to configdir/ptclient/ptsock)
ptscache_db: berkeley
The cyrusdb backend to use for the pts cache.
Allowed values: berkeley, berkeley-hash, skiplist
ptscache_timeout: 10800
The timeout (in seconds) for the PTS cache database when using the
auth_krb_pts authorization method (default: 3 hours).
ptskrb5_convert524: 1
When using the AFSKRB ptloader module with Kerberos 5 canonicalization,
do the final 524 conversion to get a n AFS style name (using '.' instead
of '/', and using short names
ptskrb5_strip_default_realm: 1
When using the AFSKRB ptloader module with Kerberos 5 canonicalization,
strip the default realm from the userid (this does not affect the stripping
of realms specified by the afspts_localrealms option)
The percent of quota utilization over which the server generates
warnings.
quotawarnkb: 0
The maximum amount of free space (in kB) in which to give a quota
warning (if this value is 0, or if the quota is smaller than this
amount, than warnings are always given).
reject8bit: 0
If enabled, lmtpd rejects messages with 8-bit characters in the
headers. Also see munge8bit, which is only applied if reject8bit is
not activated. (A proper soultion to non-ASCII characters in headers
is offered by RFC 2047 and its predecessors.)
rfc2046_strict: 0
If enabled, imapd will be strict (per RFC 2046) when matching MIME
boundary strings. This means that boundaries containing other
boundaries as substrings will be treated as identical. Since
enabling this option will break some messages created by Eudora 5.1
(and earlier), it is recommended that it be left disabled unless
there is good reason to do otherwise.
rfc3028_strict: 1
If enabled, Sieve will be strict (per RFC 3028) with regards to
which headers are allowed to be used in address and envelope tests.
This means that only those headers which are defined to contain addresses
will be allowed in address tests and only "to" and "from" will be
allowed in envelope tests. When disabled, ANY grammatically correct header
will be allowed.
sasl_auto_transition: 0
If enabled, the SASL library will automatically create authentication
secrets when given a plaintext password. See the SASL documentation.
sasl_maximum_layer: 256
Maximum SSF (security strength factor) that the server will allow a
client to negotiate. This corresponds to the max_ssf option of libsasl.
Please check the libsasl documentation for available values.
sasl_minimum_layer: 0
The minimum SSF that the server will allow a client to negotiate.
A value of 1 requires integrity protection (i.e. checksums); any higher
value requires some amount of encryption. This corresponds to the min_ssf
option of libsasl. Please check libsasl documentation for available
values.
sasl_option: 0
Any SASL option can be set by preceeding it with "sasl_". This
file overrides the SASL configuration file.
sasl_pwcheck_method: <none>
The mechanism used by the server to verify plaintext passwords.
Possible values include "auxprop", "saslauthd", and "pwcheck".
The pathname of the sendmail executable. Sieve invokes sendmail
for sending rejections, redirects and vacation responses.
servername: <none>
This is the hostname visible in the greeting messages of the POP,
IMAP and LMTP daemons. If it is unset, then the result returned
from gethostname(2) is used.
sharedprefix: Shared Folders
If using the alternate IMAP namespace, the prefix for the shared
namespace. The hierarchy delimiter will be automatically appended.
sieve_maxscriptsize: 32
Maximum size (in kilobytes) any sieve script can be, enforced at
submission by timsieved(8).
sieve_maxscripts: 5
Maximum number of sieve scripts any user may have, enforced at
submission by timsieved(8).
sievedir: /usr/sieve
If sieveusehomedir is false, this directory is searched for Sieve
scripts.
sievenotifier: <none>
Notifyd(8) method to use for "SIEVE" notifications. If not set, "SIEVE"
notifications are disabled.
This method is only used when no method is specified in the script.
sieveusehomedir: 0
If enabled, lmtpd will look for Sieve scripts in user's home
directories: ~user/.sieve.
singleinstancestore: 1
If enabled, imapd, lmtpd and nntpd attempt to only write one copy
of a message per partition and create hard links, resulting in a
potentially large disk savings.
skiplist_unsafe: 0
If enabled, this option forces the skiplist cyrusdb backend to
not sync writes to the disk. Enabling this option is NOT RECOMMENDED.
soft_noauth: 1
If enabled, lmtpd returns temporary failures if the client does not
successfully authenticate. Otherwise lmtpd returns permanant failures
(causing the mail to bounce immediately).
srvtab: <empty string>
The pathname of srvtab file containing the server's private
key. This option is passed to the SASL library and overrides its
default setting.
subscription_db: flat
The cyrusdb backend to use for the subscriptions list.
File containing the certificate presented for server authentication
during STARTTLS. A value of "disabled" will disable SSL/TLS.
tls_cipher_list: DEFAULT
The list of SSL/TLS ciphers to allow. The format of the string is
described in ciphers(1).
tls_key_file: <none>
File containing the private key belonging to the server
certificate. A value of "disabled" will disable SSL/TLS.
tls_require_cert: 0
Require a client certificate for ALL services (imap, pop3, lmtp, sieve).
tls_session_timeout: 1440
The length of time (in minutes) that a TLS session will be cached
for later reuse. The maximum value is 1440 (24 hours), the
default. A value of 0 will disable session caching.
umask: 077
The umask value used by various Cyrus IMAP programs.
username_tolower: 1
Convert usernames to all lowercase before login/authenticate. This
is useful with authentication backends which ignore case during
username lookups (such as LDAP).
userprefix: Other Users
If using the alternate IMAP namespace, the prefix for the other users
namespace. The hierarchy delimiter will be automatically appended.
unix_group_enable: 1
Should we look up groups when using auth_unix (disable this if you are
not using groups in ACLs for your IMAP server, and you are using auth_unix
with a backend (such as LDAP) that can make getgrent() calls very
slow)
unixhierarchysep: 0
Use the UNIX separator character '/' for delimiting levels of
mailbox hierarchy. The default is to use the netnews separator
character '.'.
virtdomains: off
Enable virtual domain support. If enabled, the user's domain will
be determined by splitting a fully qualified userid at the last '@'
or '%' symbol. If the userid is unqualified, and the virtdomains
option is set to "on", then the domain will be determined by doing
a reverse lookup on the IP address of the incoming network
interface, otherwise the user is assumed to be in the default
domain (if set).