Proxmox Mail Gateway

Proxmox Mail Gateway is a full-featured email security platform that sits between your firewall and your internal mail server, filtering all inbound and outbound email traffic before it ever touches your production mail infrastructure. Spam, viruses, Trojans, phishing — it catches the lot and blocks it at the perimeter.

The deployment architecture is deliberately simple and effective. PMG operates as a mail proxy, meaning your MX records point to the gateway, it processes and filters all traffic, and only clean email gets forwarded to your actual mail server (Exchange, Postfix, Zimbra, whatever you run). This "before-queue" filtering approach is critical because it rejects malicious email directly during the SMTP dialogue, which means your mail server never accepts the dodgy message in the first place — and you avoid the "backscatter" problem that gets your domain blacklisted when your server tries to bounce undeliverable spam.

Under the hood, PMG runs dual anti-virus engines: ClamAV for signature-based scanning and Commtouch/CYREN Zero-Hour Virus Outbreak Protection for real-time, cloud-based detection of brand-new threats. Anti-spam filtering uses Apache SpamAssassin with continuously updated rulesets. The advanced object-oriented rule system gives administrators precise, flexible control over mail flow — match on sender, recipient, content, attachment type, and more, with AND/OR/NOT logic that handles even complex compliance requirements.

For organisations needing redundancy, PMG supports high availability clustering that synchronises configuration and data across master and node servers via a VPN tunnel. The web-based management interface includes a Message Tracking Centre that merges all email traffic logs into a single searchable view — no more guessing where a missing email went. Deploy it as a bare-metal ISO, a VM, or a container appliance; it takes minutes to configure and starts protecting your mail infrastructure immediately.