I having a hard time working this out, I've looked in the wiki and various other places but am still cueless (stupid me)
mercury:/etc/dovecot# imtest -a graeme 203.96.154.204 S: * OK dovecot ready. C: C01 CAPABILITY S: * CAPABILITY IMAP4rev1 SORT THREAD=REFERENCES MULTIAPPEND UNSELECT LITERAL+ IDLE CHILDREN LISTEXT LIST-SUBSCRIBED NAMESPACE STARTTLS AUTH=PLAIN S: C01 OK Capability completed. Authentication failed. no mechanism available Security strength factor: 0 mercury:/etc/dovecot#
Below is my configuration file for version 0.99-14.1 on a Debian Sarge box I'm quite happy with plaintext auth for now. Any help or suggestions much appreciated.
Graeme
Dovecot 1.0 configuration file
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/dovecot
--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
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. You can specify ports with
"host:port".
#imap_listen = * #pop3_listen = *
IP or host address where to listen in for SSL connections. Defaults
to above non-SSL equilevants if not specified.
#imaps_listen = #pop3s_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
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
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
IMAP login process
login = imap
Executable location.
login_executable = /usr/lib/dovecot/imap-login
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_user 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_user
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
POP3 login process
Settings default to same as above, so you don't have to set anything
unless you want to override them.
login = pop3
Exception to above rule being the executable location.
#login_executable = /usr/lib/dovecot/pop3-login
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 = mail
':' separated list of directories under which chrooting is allowed for
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 by
giving /./ in user's home directory (eg. /home/./user chroots into /home).
#mail_chroot =
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:
%u - username
%n - user part in user@domain, same as %u if there's no domain
%d - domain part in user@domain, empty if user there's no domain
%h - home directory
You can also limit a width of string by giving the number of max.
characters
after the '%' character. For example %1u gives the first character of
username. 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 =
Space-separated list of fields to cache for all mails. Currently these
fields are allowed followed by a list of commands they speed up:
Envelope - FETCH ENVELOPE and SEARCH FROM, TO, CC, BCC, SUBJECT,
SENTBEFORE, SENTON, SENTSINCE, HEADER MESSAGE-ID,
HEADER IN-REPLY-TO
Body - FETCH BODY
Bodystructure - FETCH BODY, BODYSTRUCTURE
MessagePart - FETCH BODY[1.2.3] (ie. body parts), RFC822.SIZE,
SEARCH SMALLER, LARGER, also speeds up BODY/BODYSTRUCTURE
generation. This is always set with mbox mailboxes, and
also default with Maildir.
Different IMAP clients work in different ways, that's why Dovecot by
default
only caches MessagePart which speeds up most operations. Whenever client
does something where caching could be used, the field is automatically
marked
to be cached later. For example after FETCH BODY the BODY will be cached
for all new messages. Normally you should leave this alone, unless you
know
what most of your IMAP clients are. Caching more fields than needed makes
the index files larger and generate useless I/O.
With maildir there's one extra optimization - if nothing is cached,
indexing
the maildir becomes much faster since it's not opening any of the mail
files.
This could be useful if your IMAP clients access only new mails.
#mail_cache_fields = MessagePart
Space-separated list of fields that Dovecot should never set to be cached.
Useful if you want to save disk space at the cost of more I/O when the
fields
needed.
#mail_never_cache_fields =
Workarounds for various client bugs:
oe6-fetch-no-newmail:
Never send EXISTS/RECENT when replying to FETCH command. Outlook
Express
seems to think they are FETCH replies and gives user "Message no
longer
in server" error. 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.
outlook-pop3-no-nuls:
Outlook and Outlook Express hang if mails contain NUL characters.
This setting replaces them with 0x80 character.
#client_workarounds =
Dovecot can notify client of new mail in selected mailbox soon after it's
received. This setting specifies the minimum interval in seconds between
new mail notifications to client - internally they may be checked more or
less often. Setting this to 0 disables the checking.
NOTE: Evolution client breaks with this option when it's trying to APPEND.
#mailbox_check_interval = 0
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 custom flag name. It's only forced when trying
to create new flags.
#mail_max_flag_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.
#mail_read_mmaped = no
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
Check if mails' content has been changed by external programs. This slows
down things as extra stat() needs to be called for each file. If
changes are
noticed, the message is treated as a new message, since IMAP protocol
specifies that existing messages are immutable.
#maildir_check_content_changes = no
Which locking methods to use for locking mbox. There's three available:
dotlock: Create <mailbox>.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.
You can use both fcntl and flock too; if you do the order they're declared
with is important to avoid deadlocks if other MTAs/MUAs are using both
fcntl
and flock. Some operating systems don't allow using both of them
simultaneously, eg. BSDs. If dotlock is used, it's always created first.
#mbox_locks = dotlock fcntl
Should we create dotlock file even when we want only a read-lock? Setting
this to yes hurts the performance when the mailbox is accessed
simultaneously
by multiple processes, but it's needed for reliable reading if no other
locking methods are available.
#mbox_read_dotlock = no
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
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. Note that setting
this to yes means that log file is opened as the logged in user, which
might not work. It could also 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
IMAP process
Executable location
imap_executable = /usr/lib/dovecot/imap
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.
#imap_process_size = 256
Support for dynamically loadable modules.
#imap_use_modules = no imap_modules = /usr/lib/dovecot/imap
POP3 process
Executable location
#pop3_executable = /usr/lib/dovecot/pop3
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.
#pop3_process_size = 256
Support for dynamically loadable modules.
#pop3_use_modules = no #pop3_modules = /usr/lib/dovecot/pop3
Authentication processes
An Authentication process is a child process used by Dovecot that
handles the authentication steps. The steps cover an authentication
mechanism (auth_mechanisms, how the client authenticates in the IMAP or
POP3 protocol), which password database should be queried (auth_passdb),
and which user database should be queried (auth_userdb, to obtain
UID, GID, and location of the user's mailbox/home directory).
You can have multiple processes, though a typical configuration will
have only one. Each time "auth = xx" is seen, a new process
definition is started. The point of multiple processes is to be able
to set stricter permissions. (See auth_user below.)
Just remember that only one Authentication process is asked for the
password, so you can't have different passwords accessible through
different process definitions (unless they have different
auth_mechanisms, and you're ok with having different password for
each mechanisms).
Authentication process name.
auth = default
Specifies how the client authenticates in the IMAP protocol.
Space separated list of permitted authentication mechanisms:
anonymous plain digest-md5 cram-md5
anonymous - No authentication required.
plain - The password is sent as plain text. All IMAP/POP3 clients
support this, and the password can be encrypted by Dovecot to match
any of the encryption schemes used in password databases.
digest-md5 and cram-md5 - both encrypt the password so it is more
secure in transit, but are not well supported by clients, and
require that the password database use a matching encryption
scheme (or be in plaintext).
See auth.txt for more details.
If you are using SSL there is less benefit to digest-md5 and
cram-md5 as the communication is already encrypted.
auth_mechanisms = plain
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 =
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
passwd: /etc/passwd or similiar, using getpwnam()
passwd-file <path>: passwd-like file with specified location
static uid=<uid> gid=<gid> home=<dir template>: static settings
vpopmail: vpopmail library
ldap <config path>: LDAP, see /etc/dovecot/dovecot-ldap.conf
mysql <config path>: a MySQL database, see
/etc/dovecot/dovecot-mysql.conf
pgsql <config path>: a PostgreSQL database, see
/etc/dovecot/dovecot-pgsql.conf
auth_userdb = passwd
Password database specifies only the passwords for users.
http://wiki.dovecot.org/Authentication
passwd: /etc/passwd or similiar, using getpwnam()
shadow: /etc/shadow or similiar, using getspnam()
pam [<service> | *]: PAM authentication
passwd-file <path>: passwd-like file with specified location
vpopmail: vpopmail authentication
ldap <config path>: LDAP, see /etc/dovecot/dovecot-ldap.conf
mysql <config path>: a MySQL database, see
/etc/dovecot/dovecot-mysql.conf
pgsql <config path>: a PostgreSQL database, see
/etc/dovecot/dovecot-pgsql.conf
auth_passdb = passwd
#auth_executable = /usr/lib/dovecot/dovecot-auth
Set max. process size in megabytes.
#auth_process_size = 256
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 auth_userdb above.
auth_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.
#auth_chroot =
Number of authentication processes to create
#auth_count = 1
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 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 = no
digest-md5 authentication process. It requires special MD5 passwords which
/etc/shadow and PAM doesn't support, so we never need roots to handle it.
Note that the passwd-file is opened before chrooting and dropping root
privileges, so it may be 0600-root owned file.
#auth = digest_md5 #auth_mechanisms = digest-md5 #auth_realms = #auth_userdb = passwd-file /etc/passwd.imap #auth_passdb = passwd-file /etc/passwd.imap #auth_user = imapauth #auth_chroot =
if you plan to use only passwd-file, you don't need the two auth
processes,