Snowbox

Snowbox is a straightforward and easy-to-use POP3 server written in Perl. It can be set up in a couple of minutes and doesn't rely on editing dozens of files scattered around various configuration directories.

Despite its simplness it's a full featured POP3 server. See the feature list below. It won the "Open Source Jahrbuch" hacking contest, a programming contest where code with a maximum of 500 lines could be submitted. You can download the book and the article that mentiones Snowbox for free.

Scalability

Since it runs from inetd Snowbox is not a high performance POP3 server. However, it is certainly enough for most common use cases and the ideal solution for smaller sites that want a simple and easy to use server.

Installation:

Run "make install" in the distribution directory. This will install the Snowbox executable in /usr/local/sbin and create an initial config directory /etc/snowbox. This directory will contain two files: "config", the global configuration file for snownews, and "user.auth" which contains the users allowed to connect to the server. These files will never be overwritten if they already exist.

The configuration is pretty much self explanatory. See the manpage for more details about what can be done.

Features:

• Supports APOP authentication
• (Security) Runs as a user process once authenticated.
• (Security) No temporary file creation.
• (Security) Very small code base that is easily extensible.
• SSL is possible by using stunnel.
• Of course, all POP3 functionality is implemented, too!

What is new in this release:

• This version fixes a problem with spaces in passwords, fixes a crash in the TOP command, and adds improved mailbox file locking, among other, smaller improvements.

What is new in version 2.0:

• Snowbox has been rewritten in Go.
• It now supports SSL and IPv6, and does not rely on inetd anymore.

What is new in version 1.0:

• A disconnect timer has been added. Snowbox now exits automatically after it hasn't been sent any data within 5 minutes. Normally I thought a client that got disconnect by losing the connection would automatically cause inetd to terminate the process, but it seems I was wrong.
• The CAPA command from POP3 optional commands RFC, advertising TOP, USER, UIDL and EXPIRE NEVER has been added. Not a big deal, but, well... it does increase the feature list!

Requirements:

• Perl
• Digest::MD5