## Dovecot 1.0 configuration file # '#' character and everything after it is treated as comments. Extra spaces # and tabs are ignored. If you want to use either of these explicitly, put the # value inside quotes, eg.: key = "# char and trailing whitespace " # Default values are shown after each value, it's not required to uncomment # any of the lines. Exception to this are paths, they're just examples # with real defaults being based on configure options. The paths listed here # are for configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var # --with-ssldir=/etc/ssl # Base directory where to store runtime data. #base_dir = /var/run/dovecot/ # Protocols we want to be serving: # imap imaps pop3 pop3s #protocols = imap imaps protocols = imap imaps pop3 pop3s # IP or host address where to listen in for connections. It's not currently # possible to specify multiple addresses. "*" listens in all IPv4 interfaces. # "[::]" listens in all IPv6 interfaces, but may also listen in all IPv4 # interfaces depending on the operating system. If you want to specify ports # for each service, you will need to configure these settings inside the # protocol imap/pop3 { ... } section, so you can specify different ports # for IMAP/POP3. listen = * # IP or host address where to listen in for SSL connections. Defaults # to above if not specified. #ssl_listen = # Disable SSL/TLS support. #ssl_disable = no # PEM encoded X.509 SSL/TLS certificate and private key. They're opened before # dropping root privileges, so keep the key file unreadable by anyone but # root. #ssl_cert_file = /etc/ssl/certs/dovecot.pem #ssl_key_file = /etc/ssl/private/dovecot.pem # File containing trusted SSL certificate authorities. Usually not needed. #ssl_ca_file = # Request client to send a certificate. #ssl_verify_client_cert = no # SSL parameter file. Master process generates this file for login processes. # It contains Diffie Hellman and RSA parameters. #ssl_parameters_file = /var/run/dovecot/ssl-parameters.dat # How often to regenerate the SSL parameters file. Generation is quite CPU # intensive operation. The value is in hours, 0 disables regeneration # entirely. #ssl_parameters_regenerate = 24 # SSL ciphers to use #ssl_cipher_list = all:!LOW # Disable LOGIN command and all other plaintext authentications unless # SSL/TLS is used (LOGINDISABLED capability). Note that 127.*.*.* and # IPv6 ::1 addresses are considered secure, this setting has no effect if # you connect from those addresses. disable_plaintext_auth = no # Use this logfile instead of syslog(). /dev/stderr can be used if you want to # use stderr for logging (ONLY /dev/stderr - otherwise it is closed). #log_path = # For informational messages, use this logfile instead of the default #info_log_path = # Prefix for each line written to log file. % codes are in strftime(3) # format. #log_timestamp = "%b %d %H:%M:%S " ## ## Login processes ## # Directory where authentication process places authentication UNIX sockets # which login needs to be able to connect to. The sockets are created when # running as root, so you don't have to worry about permissions. Note that # everything in this directory is deleted when Dovecot is started. #login_dir = /var/run/dovecot/login # chroot login process to the login_dir. Only reason not to do this is if you # wish to run the whole Dovecot without roots. # http://wiki.dovecot.org/Rootless #login_chroot = yes # User to use for the login process. Create a completely new user for this, # and don't use it anywhere else. The user must also belong to a group where # only it has access, it's used to control access for authentication process. # Note that this user is NOT used to access mails. # http://wiki.dovecot.org/UserIds #login_user = dovecot # Set max. process size in megabytes. If you don't use # login_process_per_connection you might need to grow this. #login_process_size = 32 # Should each login be processed in it's own process (yes), or should one # login process be allowed to process multiple connections (no)? Yes is more # secure, espcially with SSL/TLS enabled. No is faster since there's no need # to create processes all the time. #login_process_per_connection = yes # Number of login processes to create. If login_process_per_connection is # yes, this is the number of extra processes waiting for users to log in. #login_processes_count = 3 # Maximum number of extra login processes to create. The extra process count # usually stays at login_processes_count, but when multiple users start logging # in at the same time more extra processes are created. To prevent fork-bombing # we check only once in a second if new processes should be created - if all # of them are used at the time, we double their amount until limit set by this # setting is reached. This setting is used only if login_process_per_use is yes. #login_max_processes_count = 128 # Maximum number of connections allowed in login state. When this limit is # reached, the oldest connections are dropped. If login_process_per_connection # is no, this is a per-process value, so the absolute maximum number of users # logging in actually login_processes_count * max_logging_users. #login_max_logging_users = 256 # Greeting message for clients. #login_greeting = Dovecot ready. # Space-separated list of elements we want to log. The elements which have # a non-empty variable value are joined together to form a comma-separated # string. #login_log_format_elements = user=<%u> method=%m rip=%r lip=%l %c # Login log format. %$ contains login_log_format_elements string, %s contains # the data we want to log. #login_log_format = %$: %s ## ## Mail processes ## # Maximum number of running mail processes. When this limit is reached, # new users aren't allowed to log in. #max_mail_processes = 1024 # Show more verbose process titles (in ps). Currently shows user name and # IP address. Useful for seeing who are actually using the IMAP processes # (eg. shared mailboxes or if same uid is used for multiple accounts). #verbose_proctitle = no # Show protocol level SSL errors. #verbose_ssl = no # Valid UID range for users, defaults to 500 and above. This is mostly # to make sure that users can't log in as daemons or other system users. # Note that denying root logins is hardcoded to dovecot binary and can't # be done even if first_valid_uid is set to 0. #first_valid_uid = 500 #last_valid_uid = 0 # Valid GID range for users, defaults to non-root/wheel. Users having # non-valid GID as primary group ID aren't allowed to log in. If user # belongs to supplementary groups with non-valid GIDs, those groups are # not set. #first_valid_gid = 1 #last_valid_gid = 0 # Grant access to these extra groups for mail processes. Typical use would be # to give "mail" group write access to /var/mail to be able to create dotlocks. #mail_extra_groups = # ':' separated list of directories under which chrooting is allowed for mail # processes (ie. /var/mail will allow chrooting to /var/mail/foo/bar too). # This setting doesn't affect login_chroot or auth_chroot variables. # WARNING: Never add directories here which local users can modify, that # may lead to root exploit. Usually this should be done only if you don't # allow shell access for users. See # /usr/share/doc/dovecot-common/configuration.txt for more information. #valid_chroot_dirs = # Default chroot directory for mail processes. This can be overridden for # specific users in user database by giving /./ in user's home directory # (eg. /home/./user chroots into /home). Note that usually there is no real # need to do chrooting, Dovecot doesn't allow users to access files outside # their mail directory anyway. #mail_chroot = # Enable mail process debugging. This can help you figure out why Dovecot # isn't finding your mails. #mail_debug = no # Default MAIL environment to use when it's not set. By leaving this empty # dovecot tries to do some automatic detection as described in # /usr/share/doc/dovecot-common/mail-storages.txt. # There's a few special variables you can use, eg.: # # %u - username # %n - user part in user@domain, same as %u if there's no domain # %d - domain part in user@domain, empty if there's no domain # %h - home directory # # See /usr/share/doc/dovecot-common/variables.txt for full list. Some examples: # # default_mail_env = maildir:/var/mail/%1u/%u/Maildir # default_mail_env = mbox:~/mail/:INBOX=/var/mail/%u # default_mail_env = mbox:/var/mail/%d/%n/:INDEX=/var/indexes/%d/%n # #default_mail_env = # If you need to set multiple mailbox locations or want to change default # namespace settings, you can do it by defining namespace sections: # # You can have private, shared and public namespaces. The only difference # between them is how Dovecot announces them to client via NAMESPACE # extension. Shared namespaces are meant for user-owned mailboxes which are # shared to other users, while public namespaces are for more globally # accessible mailboxes. # # REMEMBER: If you add any namespaces, the default namespace must be added # explicitly, ie. default_mail_env does nothing unless you have a namespace # without a location setting. Default namespace is simply done by having a # namespace with empty prefix. #namespace private { # Hierarchy separator to use. You should use the same separator for all # namespaces or some clients get confused. '/' is usually a good one. #separator = / # Prefix required to access this namespace. This needs to be different for # all namespaces. For example "Public/". #prefix = # Physical location of the mailbox. This is in same format as # default_mail_env, which is also the default for it. #location = # There can be only one INBOX, and this setting defines which namespace # has it. #inbox = yes # If namespace is hidden, it's not advertised to clients via NAMESPACE # extension or shown in LIST replies. This is mostly useful when converting # from another server with different namespaces which you want to depricate # but still keep working. For example you can create hidden namespaces with # prefixes "~/mail/", "~%u/mail/" and "mail/". #hidden = yes #} # Space-separated list of fields to initially save into cache file. Currently # these fields are allowed: # # flags, date.sent, date.received, size.virtual, size.physical # mime.parts, imap.body, imap.bodystructure # # Different IMAP clients work in different ways, so they benefit from # different cached fields. Some do not benefit from them at all. Caching more # than necessary generates useless disk I/O, so you don't want to do that # either. # # Dovecot attempts to automatically figure out what client wants and it keeps # only that. However the first few times a mailbox is opened, Dovecot hasn't # yet figured out what client needs, so it may not perform optimally. If you # know what fields the majority of your clients need, it may be useful to set # these fields by hand. If client doesn't actually use them, Dovecot will # eventually drop them. # # Usually you should just leave this field alone. The potential benefits are # typically unnoticeable. #mail_cache_fields = # Space-separated list of fields that Dovecot should never save to cache file. # Useful if you want to save disk space at the cost of more I/O when the fields # needed. #mail_never_cache_fields = # Like mailbox_check_interval, but used for IDLE command. #mailbox_idle_check_interval = 30 # Allow full filesystem access to clients. There's no access checks other than # what the operating system does for the active UID/GID. It works with both # maildir and mboxes, allowing you to prefix mailboxes names with eg. /path/ # or ~user/. #mail_full_filesystem_access = no # Maximum allowed length for mail keyword name. It's only forced when trying # to create new keywords. #mail_max_keyword_length = 50 # Save mails with CR+LF instead of plain LF. This makes sending those mails # take less CPU, especially with sendfile() syscall with Linux and FreeBSD. # But it also creates a bit more disk I/O which may just make it slower. #mail_save_crlf = no # Use mmap() instead of read() to read mail files. read() seems to be a bit # faster with my Linux/x86 and it's better with NFS, so that's the default. # Note that OpenBSD 3.3 and older don't work right with mail_read_mmaped = yes. #mail_read_mmaped = no # Don't use mmap() at all. This is required if you store indexes in remote # filesystems (NFS or clustered filesystem). #mmap_disable = no # Don't write() to mmaped files. This is required for some operating systems # which use separate caches for them, such as OpenBSD. #mmap_no_write = no # Locking method for index files. Alternatives are fcntl, flock and dotlock. # Dotlocking uses some tricks which may create more disk I/O than other locking # methods. #lock_method = fcntl # By default LIST command returns all entries in maildir beginning with dot. # Enabling this option makes Dovecot return only entries which are directories. # This is done by stat()ing each entry, so it causes more disk I/O. # (For systems setting struct dirent->d_type, this check is free and it's # done always regardless of this setting) #maildir_stat_dirs = no # Copy mail to another folders using hard links. This is much faster than # actually copying the file. This is problematic only if something modifies # the mail in one folder but doesn't want it modified in the others. I don't # know any MUA which would modify mail files directly. IMAP protocol also # requires that the mails don't change, so it would be problematic in any case. # If you care about performance, enable it. #maildir_copy_with_hardlinks = no # Which locking methods to use for locking mbox. There's four available: # dotlock: Create .lock file. This is the oldest and most NFS-safe # solution. If you want to use /var/mail/ like directory, the users # will need write access to that directory. # fcntl : Use this if possible. Works with NFS too if lockd is used. # flock : May not exist in all systems. Doesn't work with NFS. # lockf : May not exist in all systems. Doesn't work with NFS. # # You can use multiple locking methods; if you do the order they're declared # in is important to avoid deadlocks if other MTAs/MUAs are using multiple # locking methods as well. Some operating systems don't allow using some of # them simultaneously. #mbox_read_locks = fcntl #mbox_write_locks = dotlock fcntl # Maximum time in seconds to wait for lock (all of them) before aborting. #mbox_lock_timeout = 300 # If dotlock exists but the mailbox isn't modified in any way, override the # lock file after this many seconds. #mbox_dotlock_change_timeout = 30 # When mbox changes unexpectedly we have to fully read it to find out what # changed. If the mbox is large this can take a long time. Since the change # is usually just a newly appended mail, it'd be faster to simply read the # new mails. If this setting is enabled, Dovecot does this but still safely # fallbacks to re-reading the whole mbox file whenever something in mbox isn't # how it's expected to be. The only real downside to this setting is that if # some other MUA changes message flags, Dovecot doesn't notice it immediately. # Note that a full sync is done with SELECT, EXAMINE, EXPUNGE and CHECK # commands. #mbox_dirty_syncs = yes # Like mbox_dirty_syncs, but don't do full syncs even with SELECT, EXAMINE, # EXPUNGE or CHECK commands. If this is set, mbox_dirty_syncs is ignored. #mbox_very_dirty_syncs = no # Delay writing mbox headers until doing a full write sync (EXPUNGE and CHECK # commands and when closing the mailbox). This is especially useful for POP3 # where clients often delete all mails. The downside is that our changes # aren't immediately visible to other MUAs. #mbox_lazy_writes = yes # umask to use for mail files and directories #umask = 0077 # Drop all privileges before exec()ing the mail process. This is mostly # meant for debugging, otherwise you don't get core dumps. It could be a small # security risk if you use single UID for multiple users, as the users could # ptrace() each others processes then. #mail_drop_priv_before_exec = no # Set max. process size in megabytes. Most of the memory goes to mmap()ing # files, so it shouldn't harm much even if this limit is set pretty high. #mail_process_size = 256 # Log prefix for mail processes. # See /usr/share/doc/dovecot-common/variables.txt for list of possible # variables you can use. #mail_log_prefix = "%Us(%u): " ## ## IMAP specific settings ## protocol imap { # Login executable location. #login_executable = /usr/lib/dovecot/imap-login # IMAP executable location #mail_executable = /usr/lib/dovecot/imap # This would write rawlogs into ~/dovecot.rawlog/ directory: #mail_executable = /usr/lib/dovecot/rawlog /usr/lib/dovecot/imap # Maximum IMAP command line length in bytes. Some clients generate very long # command lines with huge mailboxes, so you may need to raise this if you get # "Too long argument" or "IMAP command line too large" errors often. #imap_max_line_length = 65536 # Support for dynamically loadable modules. #mail_use_modules = no #mail_modules = /usr/lib/dovecot/imap # Send IMAP capabilities in greeting message. This makes it unnecessary for # clients to request it with CAPABILITY command, so it saves one round-trip. # Many clients however don't understand it and ask the CAPABILITY anyway. #login_greeting_capability = no # Workarounds for various client bugs: # delay-newmail: # Send EXISTS/RECENT new mail notifications only when replying to NOOP # and CHECK commands. Some clients ignore them otherwise, for example # OSX Mail. Outlook Express breaks more badly though, without this it # may show user "Message no longer in server" errors. Note that OE6 still # breaks even with this workaround if synchronization is set to # "Headers Only". # outlook-idle: # Outlook and Outlook Express never abort IDLE command, so if no mail # arrives in half a hour, Dovecot closes the connection. This is still # fine, except Outlook doesn't connect back so you don't see if new mail # arrives. # netscape-eoh: # Netscape 4.x breaks if message headers don't end with the empty "end of # headers" line. Normally all messages have this, but setting this # workaround makes sure that Netscape never breaks by adding the line if # it doesn't exist. This is done only for FETCH BODY[HEADER.FIELDS..] # commands. Note that RFC says this shouldn't be done. # tb-extra-mailbox-sep: # With mbox storage a mailbox can contain either mails or submailboxes, # but not both. Thunderbird separates these two by forcing server to # accept '/' suffix in mailbox names in subscriptions list. #imap_client_workarounds = outlook-idle } ## ## POP3 specific settings ## protocol pop3 { # Login executable location. #login_executable = /usr/lib/dovecot/pop3-login # POP3 executable location #mail_executable = /usr/lib/dovecot/pop3 # Don't try to set mails non-recent or seen with POP3 sessions. This is # mostly intended to reduce disk I/O. With maildir it doesn't move files # from new/ to cur/, with mbox it doesn't write Status-header. #pop3_no_flag_updates = no # Support LAST command which exists in old POP3 specs, but has been removed # from new ones. Some clients still wish to use this though. Enabling this # makes RSET command clear all \Seen flags from messages. #pop3_enable_last = no # POP3 UIDL format to use. You can use following variables: # # %v - Mailbox UIDVALIDITY # %u - Mail UID # %m - MD5 sum of the mailbox headers in hex (mbox only) # %f - filename (maildir only) # # If you want UIDL compatibility with other POP3 servers, use: # UW's ipop3d : %08Xv%08Xu # Courier version 0 : %f # Courier version 1 : %u # Courier version 2 : %v-%u # Cyrus (<= 2.1.3) : %u # Cyrus (>= 2.1.4) : %v.%u # # Note that Outlook 2003 seems to have problems with %v.%u format which is # Dovecot's default, so if you're building a new server it would be a good # idea to change this. %08Xu%08Xv should be pretty fail-safe. #pop3_uidl_format = %v.%u # POP3 logout format string: # %t - number of TOP commands # %T - number of bytes sent to client as a result of TOP command # %r - number of RETR commands # %R - number of bytes sent to client as a result of RETR command # %d - number of deleted messages # %m - number of messages (before deletion) # %s - mailbox size in bytes (before deletion) #pop3_logout_format = top=%t/%T, retr=%r/%R, del=%d/%m, size=%s # Support for dynamically loadable modules. #mail_use_modules = no #mail_modules = /usr/lib/dovecot/pop3 # Workarounds for various client bugs: # outlook-no-nuls: # Outlook and Outlook Express hang if mails contain NUL characters. # This setting replaces them with 0x80 character. # oe-ns-eoh: # Outlook Express and Netscape Mail breaks if end of headers-line is # missing. This option simply sends it if it's missing. #pop3_client_workarounds = } ## ## Authentication processes ## # Executable location #auth_executable = /usr/lib/dovecot/dovecot-auth # Set max. process size in megabytes. #auth_process_size = 256 # Authentication cache size in kilobytes. #auth_cache_size = 0 # Time to live in seconds for cached data. After this many seconds a cached # record is forced out of cache. #auth_cache_ttl = 3600 # Space separated list of realms for SASL authentication mechanisms that need # them. You can leave it empty if you don't want to support multiple realms. # Many clients simply use the first one listed here, so keep the default realm # first. #auth_realms = # Default realm/domain to use if none was specified. This is used for both # SASL realms and appending @domain to username in plaintext logins. #auth_default_realm = # List of allowed characters in username. If the user-given username contains # a character not listed in here, the login automatically fails. This is just # an extra check to make sure user can't exploit any potential quote escaping # vulnerabilities with SQL/LDAP databases. If you want to allow all characters, # set this value to empty. #auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@ # Username character translations before it's looked up from databases. The # value contains series of from -> to characters. For example "#@/@" means # that '#' and '/' characters are translated to '@'. #auth_username_translation = # Username to use for users logging in with ANONYMOUS SASL mechanism #auth_anonymous_username = anonymous # More verbose logging. Useful for figuring out why authentication isn't # working. auth_verbose = yes # Even more verbose logging for debugging purposes. Shows for example SQL # queries. auth_debug = yes # Maximum number of dovecot-auth worker processes. They're used to execute # blocking passdb and userdb queries (eg. MySQL and PAM). They're # automatically created and destroyed as needed. #auth_worker_max_count = 30 auth default { # Space separated list of wanted authentication mechanisms: # plain digest-md5 cram-md5 apop anonymous mechanisms = plain # # Password database is used to verify user's password (and nothing more). # You can have multiple passdbs and userdbs. This is useful if you want to # allow both system users (/etc/passwd) and virtual users to login without # duplicating the system users into virtual database. # # http://wiki.dovecot.org/Authentication # # PAM authentication. Preferred nowadays by most systems. # Note that PAM can only be used to verify if user's password is correct, # so it can't be used as userdb. If you don't want to use a separate user # database (passwd usually), you can use static userdb. passdb pam { # [-session] [] # # -session makes Dovecot open and immediately close PAM session. Some # PAM plugins need this to work. # # If service name is "*", it means the authenticating service name # is used, eg. pop3 or imap. #args = dovecot } # /etc/passwd or similar, using getpwnam() # In many systems nowadays this uses Name Service Switch, which is # configured in /etc/nsswitch.conf. #passdb passwd { #} # /etc/shadow or similiar, using getspnam(). Deprecated by PAM nowadays. #passdb shadow { #} # passwd-like file with specified location #passdb passwd-file { # Path for passwd-file #args = #} # checkpassword executable authentication # NOTE: You will probably want to use "userdb passdb" with this. #passdb checkpassword { # Path for checkpassword binary #args = #} # SQL database #passdb sql { # Path for SQL configuration file, see /etc/dovecot/dovecot-sql.conf for example #args = #} # LDAP database #passdb ldap { # Path for LDAP configuration file, see /etc/dovecot/dovecot-ldap.conf for example #args = #} # vpopmail authentication #passdb vpopmail { #} # # User database specifies where mails are located and what user/group IDs # own them. For single-UID configuration use "static". # # http://wiki.dovecot.org/Authentication # http://wiki.dovecot.org/VirtualUsers # # /etc/passwd or similar, using getpwnam() # In many systems nowadays this uses Name Service Switch, which is # configured in /etc/nsswitch.conf. userdb passwd { } # passwd-like file with specified location #userdb passwd-file { # Path for passwd-file #args = #} # static settings generated from template #userdb static { # Template for settings. Can return anything a userdb could normally # return, eg.: uid, gid, home, mail, nice # # A few examples: # # args = uid=500 gid=500 home=/var/mail/%u # args = uid=500 gid=500 home=/home/%u mail=mbox:/home/%u/mail nice=10 # #args = #} # SQL database #userdb sql { # Path for SQL configuration file, see /etc/dovecot/dovecot-sql.conf for example #args = #} # LDAP database #userdb ldap { # Path for LDAP configuration file, see /etc/dovecot/dovecot-ldap.conf for example #args = #} # vpopmail #userdb vpopmail { #} # "passdb" user database means that the passdb already provided the # needed information and there's no need to do a separate userdb lookup. # This can be made to work with SQL and LDAP databases. # http://wiki.dovecot.org/AuthSpecials userdb passdb { } # User to use for the process. This user needs access to only user and # password databases, nothing else. Only shadow and pam authentication # requires roots, so use something else if possible. Note that passwd # authentication with BSDs internally accesses shadow files, which also # requires roots. Note that this user is NOT used to access mails. # That user is specified by userdb above. user = root # Directory where to chroot the process. Most authentication backends don't # work if this is set, and there's no point chrooting if auth_user is root. # Note that valid_chroot_dirs isn't needed to use this setting. #chroot = # Number of authentication processes to create #count = 1 # Require a valid SSL client certificate or the authentication fails. #ssl_require_client_cert = no } # It's possible to export the authentication interface to other programs, # for example SMTP server which supports talking to Dovecot. Client socket # handles the actual authentication - you give it a username and password # and it returns OK or failure. So it's pretty safe to allow anyone access to # it. Master socket is used to a) query if given client was successfully # authenticated, b) userdb lookups. # listener sockets will be created by Dovecot's master process using the # settings given inside the auth section #auth default_with_listener { # mechanisms = plain # passdb passwd { # } # userdb pam { # } # socket listen { # master { # path = /var/run/dovecot-auth-master # # WARNING: Giving untrusted users access to master socket may be a # # security risk, don't give too wide permissions to it! # #mode = 0600 # # Default user/group is the one who started dovecot-auth (root) # #user = # #group = # } # client { # path = /var/run/dovecot-auth-client # mode = 0660 # } # } #} # connect sockets are assumed to be already running, Dovecot's master # process only tries to connect to them. They don't need any other settings # than path for the master socket, as the configuration is done elsewhere. # Note that the client sockets must exist in login_dir. #auth external { # socket connect { # master { # path = /var/run/dovecot-auth-master # } # } #}