GNU parallel is a shell tool for executing jobs in parallel locally or using remote computers. A job is typically a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. If you use xargs today you will find GNU parallel very easy to use, as GNU parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU parallel as input for other programs.
spamdyke is a drop-in filter for qmail to provide connection-time blacklisting, graylisting, DNS RBL/RHSBL checking, sender MX checking, improved logging, and more. spamdyke will provide SMTP AUTH and TLS to unpatched qmail servers. Installing spamdyke does not require patching or recompiling qmail.
Clam AntiVirus is an anti-virus toolkit designed especially for email scanning on mail gateways. It provides a number of utilities, including a flexible and scalable multi-threaded daemon, a commandline scanner, and a tool for automatic database updates. The core of the package is an anti-virus engine available as a shared library.
GNU m4 is an implementation of the traditional Unix macro processor. It is mostly SVR4 compatible, although it has some extensions (for example, handling more than 9 positional parameters to macros). GNU m4 also has built-in functions for including files, running shell commands, doing arithmetic, etc. Autoconf needs GNU m4 for generating `configure' scripts, but not for running them.
ClearOS is an integrated network server gateway solution for small and distributed organizations. The software provides all the necessary server tools to run an organization including email, anti-virus, anti-spam, file sharing, groupware, VPN, firewall, intrusion detection/prevention, content filtering, bandwidth management, multi-WAN, and more. You can think of it as a next generation small business server. Through the intuitive Web-based management console, an administrator can configure the server software along with integrated cloud-based services.
Horde Groupware Webmail Edition is an enterprise ready browser-based communication suite. Users can read, send, and organize email messages and manage and share calendars, contacts, tasks, and notes with the standards compliant components from the Horde Project. It bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag, and Mnemo. It can be extended with any of the released Horde applications or the Horde modules that are still in development, like a file manager, a bookmark manager, a forum, or a wiki.
Policyd v2 (codenamed "cluebringer") is a multi-platform policy server for popular MTAs. This policy daemon is designed mostly for large scale mail hosting environments. The main goal is to implement as many spam combating and email compliance features as possible while at the same time maintaining portability, stability, and performance. Its features include detailed policy and group specification, access control, helo/ehlo checks (helo randomization prevention and RFC compliance), SPF checks, Greylisting, Quotas, and Amavisd-new integration.
Maildrop is a powerful email filter/delivery agent. It supports mbox-style mailboxes and maildirs (a mail storage format used by Qmail). Its mail filtering language supports RFC822 parsing and GDBM/Berkeley DB database files. The maildrop package also includes a command-line tool to perform various operations on MIME messages.