dovecot-pigeonhole 0.5.19 Dovecot Sieve mail filtering plug-in and ManageSieve service

Pigeonhole adds support for the Sieve language (RFC 5228) and the ManageSieve protocol (RFC 5804) to the Dovecot e-mail server.

Sieve is a language for filtering incoming mail. Messages can be forwarded or sorted into separate folders. Unwanted messages can be rejected or discarded, and, when the user is not available, the Sieve interpreter can send an automated reply.

Sieve is meant to be simple, extensible, and system-independent. The intention is to make it impossible to write anything more complex (and dangerous) than simple mail filters. Unlike most other mail filtering script languages, Sieve does not allow users to execute arbitrary programmes.

Through the ManageSieve protocol, users can remotely manage their Sieve scripts without needing file system access. The server accepts only valid scripts to prevent embarrassing errors later on.