Pigeonhole Sieve: Include Extension

The Sieve include extension (RFC 6609) permits users to include one Sieve script into another. This can make managing large scripts or multiple sets of scripts much easier, and allows a site and its users to build up libraries of scripts. Users are able to include their own personal scripts or site-wide scripts.

Included scripts can include more scripts of their own, yielding a tree of included scripts with the main script (typically the user’s personal script) at its root.


The include extension is available by default. The include extension has its own specific settings. The following settings can be configured for the include extension (default values are indicated):

sieve_include_max_includes = 255

The maximum number of scripts that may be included. This is the total number of scripts involved in the include tree.

sieve_include_max_nesting_depth = 10

The maximum nesting depth for the include tree.