Proxmox, known for developing the Proxmox Virtual Environment distribution for deploying virtual server infrastructures, has released Proxmox Mail Gateway 8.1, presented as a ready-made solution for quickly establishing a monitoring system for email traffic and protecting the internal mail server.
The installation ISO image is available for free download. Distribution-specific components are open under the AGPLv3 license. For updates, there is both a paid Enterprise repository and two free repositories that differ in the level of update stabilization. The system component of the distribution is based on the Debian package base. Components of Proxmox Mail Gateway can be installed on top of already running servers Debian-based systems.
Proxmox Mail Gateway operates as a proxy server, serving as a gateway between the external network and the internal mail proxy server systems based on MS Exchange, Lotus Domino, or Postfix. It allows management of all incoming and outgoing email flows. All correspondence logs are analyzed and available for review through a web interface. Both graphs to assess overall dynamics and various reports and forms for obtaining information about specific emails and delivery status are provided. Cluster configurations are supported for high availability (operating a synchronized backup server, with data synchronized through an SSH tunnel) or load balancing.
A complete set of tools is provided to ensure protection, spam filtering, phishing, and virus prevention. ClamAV and Google Safe Browsing are used to block malicious attachments, and a comprehensive approach based on SpamAssassin is offered to combat spam, including support for sender verification, SPF, DNSBL, greylisting, Bayesian classification, and blocking based on spammer URI databases. For legitimate correspondence, a flexible filtering system is provided, allowing rules to be set for mail processing based on domain, recipient/sender, time of receipt, and content type.
Key innovations:
- Synchronized with the Debian 12.5 package base. The Linux kernel has been updated to release 6.5. The implementation of the ZFS file system has been updated to OpenZFS 2.2.2.
- Updated versions of the spam filtering system SpamAssassin 4.0.0, antivirus ClamAV 1.0.3, and the PostgreSQL database 15.6.
- The rule system has been expanded by allowing match-if-mode checks on objects and groups, enabling the setting of multi-level conditions that evaluate records in objects (What/Who/When) and covering multiple objects during checks. This change allows for the creation of complex rules, such as excluding specific recipients; flexibly checking attachments where the file extension does not match the MIME type; selecting emails sent from a designated address that contain specific text in the subject; selectively processing emails with certain attachments that triggered spam or virus checks.
- Management of large systems in the web interface has been simplified: the ability to filter content and search within lists of domains, transports, networks, and objects in the rule system has been added.
- User names containing fewer than 4 characters are now allowed.
- Support for optional DKIM signature formation based on the content of the "From" header, rather than the sender data transmitted during the SMTP session (MAIL FROM), has been implemented.
- Support for verified boot in UEFI Secure Boot mode has been added, ensuring that only verified components with correct digital signatures are used during boot. A shim boot loader, signed with a digital signature recognized by most hardware with UEFI, is provided for UEFI Secure Boot.
- Postfix settings have been changed to protect against SMTP Smuggling attacks, according to recommendations from Postfix developers.
- The time format in logs has been changed to comply with RFC-3339 requirements.
Source: opennet.ru
