Dovecot Settings Types

String

String settings are typically used with variable expansion to configure how something is logged. For example imap_logout_format:

imap_logout_format = in=%i out=%o

The # character and everything after it are comments. Extra spaces and tabs are ignored, so if you need to use these, put the value inside quotes. The quote character inside a quoted string is escaped with \":

key = "# char, \"quote\", and trailing whitespace  "

Unsigned integer

Unsigned integer is a number between 0..4294967295, although specific settings may have additional restrictions.

Boolean

Boolean settings interpret any value as true, or false.

yes and no are the recommended values. However, y and 1 also work as yes. Whereas, only no will work as false.

All these are case-insensitive. Other values give errors.

Size

The size value type is used in Dovecot configuration to define the amount of space taken by something, such as a file, cache or memory limit. The size value type is case insensitive. The following suffixes can be used to define size:

  • B = bytes

  • K = kilobytes

  • M = megabytes

  • G = gigabytes

  • T = terabytes

The values can optionally be followed by “I” or “IB”. For example K = KI = KIB. The size value type is base 2, meaning a kilobyte equals 1024 bytes.

Time

The Time value is used in Dovecot configuration to define the amount of Time taken by something or for doing something, such as a sending or downloading file, processing, and more. The Time value supports using suffixes of any of the following words:

secs, seconds, mins, minutes, msecs, mseconds, millisecs, milliseconds, hours, days, weeks

Note

So for example “d”, “da”, “day”, “days” all mean the same.

  • Time Interval:

    Combination of a positive integer number and a time unit. Available time units are mentioned above. To match messages from last week, you may specify

For example:

since 1w, since 1weeks or since 7days.

Millisecond Time

Same as Time, but support milliseconds precision.

IP Addresses

The IP can be IPv4 address like 127.0.0.1, IPv6 address without brackets like ::1, or with brackets like [::1]. The DNS name is looked up once during config parsing, e.g. host.example.com. If a /block is specified, then it’s a CIDR address like 1.2.3.0/24. If a /block isn’t specified, then it defaults to all bits, i.e. /32 for IPv4 addresses and /128 for IPv6 addresses.

URL

Special type of String setting. Conforms to Uniform Resource Locators (URL) (RFC 1738).