Open Software Contributions

2024Sight contributes to Open Software. Some contributions are small, some are larger. We list a few name-worthy ones below.


MailZu is a simple and intuitive interface to manage quarantining of email by Amavis-new. The 2024Sight version of MailZu, which is called MailZu-ng-da, allows users to manage for themselves Deny/Allow lists.

Regardless of the number of e-mail addresses a user may have, the user is presented with a single Deny/Allow list entry for an external email address or domain for which a list entry is to be created. The choice is then to Deny, Allow or create a Softlist entry. The latter is a capability, supported by Amavis, to use numeric Deny and Allow list values like a kind of spam offset. Users may also create Deny/Allow list entries which apply to the local part of an email address or which apply to a domain, but not any sub-domains. Normal, default, matching applies to full email addresses or domains and their sub-domains.

The list interface allows users to import and export Deny/Allow lists in a convenient CSV format. This enables users to make their own backups of their Deny/Allow list settings and to re-import them.

Administrators may manage Deny/Allow list entries at more granular level than users but 2024Sight has found that there has rarely been a need for that.

This version of MailZu can report to users by means of an e-mail the status of the user’s quarantine without the user having to log in to MailZu. This way users can easily determine whether there is something held in quarantine unexpectedly which they may then release using the MailZu-ng-da functionality.

While this version of MailZu covers more than most, it is not a complete Amavis management suite yet. It is lacking certain aspects of user and policy management, which are not normally used but should be available for completeness. There is also the question of how to obtain the actual “from” e-mail address on a message as most Mail User Agents (MUA) will show the “Display Name” only. 2024Sight uses an extension to Outlook to achieve this but that is hardly a generic solution. If there is interest, Amavis/MailZu-ng-da can be extended very elegantly to help out in this area without a requirement to change the MUA in any way.

2024Sight uses MailZu and Amavis in combination with Postfix. For this version of MailZu the Postfix terminology of Deny/Allow lists has been adopted. However, there is no inherent dependency on Postfix. As long as Amavis is available, this version should be made to work.

The 2024Sight version of MailZu may be found here.

Nagios Plug-Ins

Nagios is the industry standard in IT infrastructure monitoring. We have coded and contributed three plug-ins to the Nagios Plug-In Exchange:

·  Check-Wrapper wraps an test envelope around any Nagios Plug-In. It allows logging of Plug-In invocations and it allows simulation of errors and their resolution with the objective to check the response of the Nagios system.

·  Check-Modules assists with monitoring computer hardware and checks that all drivers for a specific computer have been loaded.

·  Check-Inactive is a security related module that checks that logged-in users on servers are active. System administrators in particular have the tendency to log-in on several machines in the course of a day and then forget to log-out again. This module monitors the user’s inactivity and raises an alarm after a pre-defined time.


Samhain is a highly configurable, host-based integrity monitoring system. Over the years 2024Sight has gained extensive experience running this system both in supervised and unsupervised applications. We have contributed certain functional enhancements, in particular in the area of TCP/UDP port scanning. Please refer to the Samhain release notes for a precise description.