The upcoming Halon 5.1 release introduces a new SMTP server proxy script. It’s configured to be executed before specific (or all) SMTP commands, even command which isn’t recognised by the SMTP server. In this blog we’ll describe how to implement our proposed SMTP LANG extension using this new script hook. First of all, we announce the LANG extension and the languages supported in the HELO script:
Deployment of changes or new features can be challenging, time-consuming and risky. Many service providers don’t have the infrastructure for production testing.
One great way of quickly and safely rolling out changes is blue-green deployment. Halon provides built-in, integrated traffic splitting that we call live staging. It’s a unique method that allows you to try out new code and configuration on a production host for only a selected part of your traffic, selected by random or IP address. This creates two virtual environments. The code editor and tooling makes it easy to test the working copy before you decide to deploy.
If you are using an on-prem, open source based solution for your MTA, you have the advantage of low initial investment costs with no license cost. But later on, your operating costs can start to become quite severe. Factors that can become quite expensive for an email service provider is server rents or costs for hardware, as well as various costs for updates, maintenance and development. Additional support costs can reside depending on the setup. You may also experience issues with complicated pathways, and various components may be coupled together in complex ways.
As a supporting member, we’re happy to be participating in our 7th meeting on February 18-21. M3AAWG meetings are an exceptional opportunity to discuss the latest in messaging security with other professionals in a focused environment of working sessions and educational panels.
We would be delighted if you joined the transport encryption session that I’m speaking at, on Wednesday. Also, if you want to meet up, just get in touch! We’re all around; product, sales and engineering.
We celebrate the new year with news on the upcoming release, which bundles many exciting features.
First and foremost, the new RESTful API with an OpenAPI specification makes integration into various development and deployment toolchains much more enjoyable. Since most of our customers already integrate Halon into their directories and control panels by making REST queries from Halon, it makes perfect sense that Halon can be provisioned in the same way.
Secondly, we’re introducing a new end-of-DATA script that’s executed once per message, as opposed to the per-recipient DATA script. Whereas the per-recipient version is convenient when you want to treat each recipient individually and let the Halon software take care of queueing and consolidating the respective actions into an SMTP response, the per-message version gives you maximum flexibility and control over execution. The $transaction variable is populated gradually during the SMTP conversation with sender information, and an array with recipients accepted by each RCPT TO command. To then relay a message to its recipients, you call Queue() for each $transaction["recipients"] and then Accept(). Making per-recipient message modifications using the MIME() class is now easier thanks to the new snapshot() and restore() methods.
The code editor’s built-in CSV editor now supports custom form controls, defined like a “schema” on a per-file basis using a JSON format. You can use checkboxes for booleans, select controllers for enumerated types, and input fields with validation for things like dates, email addresses or any regular expression you like. It makes it much more convenient and safe to create and edit lists and settings that you want to have in your Halon configuration file.
There’s a new LDAP() class that replaces the previous ldap_ functions and LDAP settings in the configuration. It provides greater flexibility, and an improved usage pattern using an iterable LDAP result object.
Finally, there are massive under-the-hood improvements. There’s a new on-disk YAML configurations with JSON schemas and Protobuf control sockets, which is used by the componentised Linux package’s new Visual Studio Code plugin and command line tools. The integrated package is built on FreeBSD 12, which ships with OpenSSL 1.1 and thus TLS 1.3 support. It was published as a standard by IETF in August last year, and is much anticipated as it contains many security improvements over previous TLS versions. The queue database is now using the latest and greatest PostgreSQL version 11.1, and the queue is automatically migrated on boot as usual.
We have that you’ll like this new release as much as we do! Check out the full changelog on GitHub for more information, and familiarise yourself with the important changes outlined in the release notes document before upgrading.
Halon are going to Smau 2018 in Milan on October 23-25, with our new distributor AnswerVAD. We have had the fortune to be introduced to this big Italian event through Massimo, the CEO of AnswerVAD. This is an innovation event, and a great place to be for announcing our presence in the region. We will be in a booth together with AnswerVAD. If you are interested of going there but don’t have a ticket, don’t hesitate to contact us and we will sign you up for free. Hope to se you in Milan!
Halon 4.0 introduced a feature we call “live staging” where you can deploy multiple running configurations at the same time, with per-connection conditions. It allows you to reliably rollout changes or new features to a production system for only a few testing IPs, or a select percentage of the traffic. With Halon 4.7, we proudly present “live debugging” using which you can add logpoints to your scripts. It enables you to inspect the full context of SMTP transactions in real-time, using the live staging conditions as connection selector.
Those points are added directly to the Monaco-based IDE, and results are inspected on a per-connection basis. You can create multiple points, triggered by multiple messages, and jump back and forth between them.
Authenticated Received Chain (ARC) is a proposed standard that have been developed to help address issues with DMARC and certain forwarders, such as mailing lists. It defines a standard for how to pass authentication results from one intermediary to another, making this information available to the recipient system. It works even in the case of multiple intermediaries, a.k.a. a chain
DMARC verifies the sender authenticity, as specified by the RFC5322.From header domain name, using SPF and DKIM. Certain indirect email flows such as mailing lists break this by altering the message, while maintaining the original From header. It causes issues for both senders that publish a DMARC policy, and receivers that verify DMARC. The two large mailbox providers AOL and Yahoo published a p=reject DMARC policy for their domains in 2014, causing some disruption for senders on those domains. It occurred when emailing recipients on mailbox services that verifies DMARC via for example mailing lists. This was, and still is, remedied by ad-hoc solutions.
ARC in itself isn’t a reputation system. The specification doesn’t define how the reputation of intermediates should be tracked, nor how public lists should be operated. In other words, as a recipient mailbox provider you still have to operate such systems in order to make use of the information that ARC provides. DMARC.org announced ARC at a M3AAWG meeting in Atlanta, 2015, where it’s been a frequent topic ever since.
$chain = ARC::chainValidate();
if ($chain["status"] == "pass" or $chain["status"] == "none")
"201805", "example.com", "pki:arc",
->SPF(["smtp.client-ip" => $senderip])
->addMethod("arc", $chain["status"], ["header.oldest-pass" => $chain["oldestpass"] ?? "0"])
We have just released an implementation for ARC (draft 14) on Github, which supports both verification and (re)sealing. It’s written in Halon script, and we’re using it on our own domain to start with. If you’re interested in taking it for a spin, just let us know.
The very successful TES security roundtable meetings are continuing. This time it brings us to London, UK on May 24th.
The meeting will revolve around DMARC, DANE, email encryption techniques, password protection and SMTP transport protection. Vittorio Bertola, Head of Policy and Innovation at Open-Xchange has assemblied a great line-up. The meeting is an exclusive invite-only event for people working with email infrastructure issues.
M3AAWG meetings are an exceptional opportunity to discuss the latest in messaging security with other professionals in a focused environment of working sessions and educational panels. This time we meet in Munich, Germany. Leading industry experts, researchers and public policy officials address such diverse topics as bot mitigation practices, social networking abuse, mobile abuse and pending legislation.
As an official supporter member, we will of course participate in the Munich meeting on June 4th-7th. If you want to meet up, just get in touch!
The Halon MTA is a flexible email operations and security platform.
It enables organisations that operate large-scale email services to offer competitive features by rapid implementation
and to lower maintenance costs through reliable deployment and reduced complexity.