The email platform for hosting providers

Halon is a full-stack email delivery platform that is open and scriptable, targeted specifically at large-scale email infrastructures.

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Bare metal
video, serial
Virtualization
VMware, Hyper-V, universal
Cloud providers
EC2, GCE, Azure, Rackspace
Version
Halon 3.3-r3 release notes
Kernel
FreeBSD 10.1

Halon is an email software distribution. It provides a full stack, scriptable approach to functions such as delivery (SMTP/LMTP), routing, security (anti-spam, signing), automation and integration; everything you need in front of your email storage.

You could think of it as a flexible and scriptable email engine, designed to be run as of a fault tolerant and linearly scalable cluster that integrates with surrounding modules and infrastructure. This highly differentiated platform enables demanding organizations like hosting providers and MSPs to implement ideal solutions for their specific needs.

It is rare that I recommend a commercial product at all, but this deserves it. It is very robust and easy to follow the flow of emails.

Peter Magnusson, Crystone

In- and outbound anti-spam and routing for Atomia-based web hosting.

Anti-spam and routing using RESTful control panel integration for shared hosting, Exchange and VPS.

Uses Halon to provide email security as a service for various platforms.

Transparent proxy for VPS hosting to prevent blacklisting and ensure deliverability.

Consolidates all in-flight-email functions

The Halon email platform includes all the functionality that you need in front of your email storage; email routing, anti spam, signing, rate limits, content filtering, outbound deliverability and much more, in an integrated and scriptable fashion. This reduces complexity and eliminates the burden of maintaining many separate systems.


Fits hosting perfectly

Many hosting providers are also software developers; the competition requires them to innovate beyond what standard products can support. Halon is the open, scriptable alternative to building and maintaining a home-brew system. Its email-centric scripting language enables you to rapidly architect the system that you need, without compromises. There are official plugins for cPanel, WHMCS and Parallels that you can build upon.


Developer friendly

Halon’s email-centric scripting language helps service providers to do rapid implementation of new technologies in a way that fits them, to keep up with the competition. Examples we’ve seen are DKIM signing with keys delivered from a control panel using a REST API, custom SRS, dynamic routing and tailored outbound policies for maximum deliverability. The sandbox, REPL interpreter and revision management make deployments safe and efficient.

if (!$senderip) {
    SetProtocol("smtp"); // Use SMTP for locally generated DSNs
    Try();
}
$route cache ["ttl" => 3600http("$apiurl/route", [], [$recipientdomain]);
$route json_decode($route);
if (!is_array($route))
    Reschedule(3600, ["reason" => "Invalid route""increment_retry" => false]);
SetDestination($route["storage"]);
SetProtocol("lmtp"); 

Outbound deliverability

Successfully delivering email is important for webhosts, ESPs and even VPS providers. The scripting language lets you design and tailor the logic to handle compromised accounts and abusive users; in order to avoid blacklisting without bothering legitimate users. You could for example combine rate limit with anti-spam, delivery failure rate and queue length for a specific sender, source-hash sender domains, send suspicious email out through a separate “bulk” IP, and control outbound connection concurrency. It can even function as a fully transparent proxy. The scriptable reporting provides comprehensive delivery reporting and analysis. Finally, thanks to the DKIM (based on our library) module’s tight integration it provides signing at blazing speeds.


Reliable, painless updates

Update your entire email delivery platform (that you’ve architected using our high-level scripting language) with a few clicks (or halonctl), instead of having to update many small software components in several different systems, worrying about regressions or broken dependencies. By completely overwriting the system partition from an update partition, updates are quick and reliable.


Enterprise security

Halon’s integrated and scriptable approach to anti-spam, signing and verification, policies and inspection enables enterprise-grade security at hosting-grade performance and at a price that fits your business model. Transaction safety (in-transit reject) and anti-spam from leading vendors make your customers forget about spam, without worrying about losing genuine email.