AfterLogic ManageSieve Server is an open-source Linux daemon which adds ManageSieve capabilities to mail servers which lack it.

Sieve pros and cons

Nowadays, many mail servers for Linux feature the support of Sieve filters which let administrators set vacation messages, forwarding, mail filtering and automatic processing, and much more. In short, Sieve filters are cool.

However, Sieve filters are just files. It's easy for an administrator to create such a file but it's not always so for applications. For instance, they may run on other computers or under privileges of the users which may not have access to Sieve files.

ManageSieve is the solution

ManageSieve protocol solves the problem. It lets applications, wherever they are, set or read Sieve filters in a manner of network protocol (like IMAP). It's also handy for web applications which usually do not have access to mail server files even when run on the same computer as the mail server.

The only drawback is that ManageSieve is still not so widely supported as plain Sieve filters. But there is the solution - AfterLogic ManageSieve Server! No need to replace your existing mail server and migrate all the data.

How it works

You install AfterLogic ManageSieve Server on the same system which runs your mail server, perform some basic configuration to let it know where to look for Sieve files in your mail server data storage and how to authenticate users (or use the same password for all accounts).

Now, ManageSieve-enabled mail clients (such as Thunderbird with ManageSieve plugin or AfterLogic WebMail Pro) can set and read Sieve filters of mail users.

If you want Sieve functionality only for webmail users, you can disable ManageSieve port access in your firewall for non-local IP addresses.

Which mail servers are supported

It was primarily developed for Courier but should also work with most Linux mail servers which store Sieve filters as files. Of course, the MTA must support Sieve filters themselves.

Such MTA as Exim supports Sieve filters directly. Others (like Postfix) can deliver to IMAP server like Dovecot which does actual Sieve filtering.

Dovecot may also provide its own ManageSieve implementation but it's not always there by default so you may need to patch it. If that's not an option for you, AfterLogic ManageSieve Server can solve the problem.