This documentation is for Dovecot v1.x, see wiki2 for v2.x documentation.
Differences between revisions 12 and 14 (spanning 2 versions)
Revision 12 as of 2007-06-29 20:34:48
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Comment: Document the %X modifier
Revision 14 as of 2007-11-03 12:49:40
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Editor: 97-83-113-92
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 * test
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 * %a - Local port (v1.1+)
 * %b - Remote port (v1.1+)


You can use special variables in several places:

  • [:MailLocation:mail_location] setting and [:Namespaces:namespace] locations

  • [:UserDatabase/Static:static userdb] and [:AuthDatabase/PasswdFile:passwd-file userdb] template strings

  • [:AuthDatabase/LDAP:LDAP] and [:AuthDatabase/SQL:SQL] userdb query strings

  • log prefix for imap/pop3 process
  • [:Plugins:Plugin] settings

  • test

The variables that work everywhere are:

  • %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
  • %s - service (IMAP, POP3, smtp, deliver (unfortunately mixed casing is used))
  • %p - PID of the current process (login or imap/pop3 process)
  • %l - local IP address
  • %r - remote IP address

These variables work almost everywhere else except in Dovecot-auth (userdb queries/templates):

  • %h - home directory
  • %i - UNIX UID of the user

These variables work only in Dovecot-auth:

  • %w - plaintext password from plaintext authentication mechanism
  • %m - authentication method (eg. PLAIN) (since v1.0.rc27)
  • %a - Local port (v1.1+)
  • %b - Remote port (v1.1+)
  • %c - "secured" string with SSL, TLS and localhost connections. Otherwise empty. (since v1.0.rc27)

These variables work only in login_log_format_elements setting:

  • %m - authentication method (eg. PLAIN)
  • %a - Local port
  • %b - Remote port
  • %c - SSL, TLS or empty


You can apply a modifiers for each variable (eg. %Ls = pop3):

  • %L - lowercase
  • %U - uppercase
  • %E - escape '"', "'" and '\' characters by inserting '\' before them. Note that variables in SQL queries are automatically escaped, you don't need to use this modifier for them.
  • %X - parse the variable as a base-10 number, and convert it to base-16 (hexadecimal)
  • %R - reverse the string
  • %H - take a 32bit hash of the variable and return it as hex. You can also limit the hash value. For example %256Hu gives values 0..ff. You might want padding also, so %2.256Hu gives 00..ff. This can be useful for example in dividing users automatically to multiple partitions. Note that if you're hashing usernames being in user@domain form, you probably want to reverse the string to get better hash value variety, eg. %3RHu.
  • %M - return the string's MD5 sum
  • %D - return "" as "sub,dc=domain,dc=org" (for LDAP queries)

You can take a substring of the variable by giving optional offset followed by '.' and width after the '%' character. For example %2u gives first two characters of the username. %2.1u gives third character of the username.

If the offset is negative, it counts from the end, for example %-2.2i gives the UID mod 100 (last two characters of the UID printed in a string). If a positive offset points outside the value, empty string is returned, if a negative offset does then the string is taken from the start.

If the width is prefixed with zero, the string isn't truncated, but only padded with '0' character if the string is shorter. For example %04i may return "0001", "1000" and "12345". %1.04i for the same string would return "001", "000" and "2345".

Type in %% to get a literal percent sign.

None: Variables (last edited 2010-06-02 15:02:14 by TimoSirainen)