Proxmox Mail Gateway — Open-Source Email Security for Australian Businesses
Email security that sits in front of your mail server — not inside it.
Proxmox Mail Gateway is an open-source email security gateway that filters inbound and outbound mail before it reaches your internal mail server. SpamAssassin scoring and ClamAV antivirus sit in front of Exchange, Microsoft 365, or any mail server — managed from one web console. PIP deploys and supports Proxmox Mail Gateway across Australia.
What is Proxmox Mail Gateway?
Proxmox Mail Gateway (PMG) is an open-source email security platform — a full mail proxy, not an add-on or plugin. It deploys as a mail transfer agent between the internet and your internal mail server, filtering every message that passes through. Inbound mail is screened for spam, viruses, trojans and phishing; outbound mail is checked against policy before it leaves.
The mail gateway runs on Debian Linux and is managed from a browser-based interface consistent with Proxmox VE. Because the gateway sits outside your mail server, it keeps threats away from the server entirely rather than cleaning up after delivery — and it keeps working even while the internal mail server is down, queuing messages until it returns.
What Proxmox Mail Gateway Filters
Every message is scored and scanned before delivery. PMG covers the four threat categories that matter most for business email.
Spam
SpamAssassin rule-based scoring with continuously updated rulesets and customisable thresholds. From PMG 9.1, the quarantine shows the positive and negative score components, so every spam filtering decision is transparent.
Malware & Viruses
ClamAV scans every message and attachment against regularly updated virus definitions. Known malware and trojans are caught at the gateway and quarantined before they reach a single mailbox.
Phishing & Trojans
Content analysis, DNSBL blacklist checking and sender-reputation scoring identify phishing and impersonation attempts. Suspect senders are filtered out before the message reaches users.
Policy & Compliance
An object-oriented rule system drives outbound filtering and domain-based policy routing — block, redirect or flag messages by sender, recipient, content or attachment type, with full whitelist and blacklist control.
Quarantine Management
The quarantine is where mail administration happens day to day. PMG puts that control in the hands of both users and administrators.
End-User Quarantine
A secure web-based quarantine lets recipients review and release their own held messages without an admin ticket. Administrators still manage the quarantine centrally across every domain, with full logging of who released what.
Shared Mailbox Support
PMG 9.1 adds mark-as-seen for shared mailboxes, so a support@ address reviewed by several users no longer causes duplicate work or accidental misreleases. Quarantined HTML images are blocked by default — on-demand loading keeps tracking pixels from firing.
Spam Score Transparency
Each quarantined message shows its spam score broken into positive and negative components, so a borderline decision is explainable rather than a black box. A copyable quarantine login link makes provisioning user access quick and secure.
Key Features
Beyond filtering, PMG is a complete mail services platform — flexible routing, encrypted transport, resilient mail flow and integrated backup.
Object-Oriented Rule System
A flexible rule engine routes and filters mail by sender, recipient, time of day, content and spam score. The same configuration drives both inbound filtering and outbound policy, so a single, scalable rule set governs all mail flow.
Multi-Domain and TLS
Manage multiple email domains with separate policies from one console. TLS transport keeps mail secure in transit, inbound and outbound, so messages between your gateway and partner servers stay encrypted end to end.
High Availability
Run multiple PMG nodes with load balancing for resilient, scalable mail flow. If one node fails, mail keeps moving — no single point of failure in front of your mail server, and no lost incoming messages.
Backup, Relay and Reporting
PMG 9.1 adds native client-side encrypted backup to Proxmox Backup Server. An SMTP relay handles outbound mail for any server, and statistical reporting surfaces mail volume, spam rates and delivery metrics — with automated logging throughout for a secure audit trail.
PMG with Microsoft Exchange and 365
The most common deployment for Australian businesses is PMG in front of Microsoft Exchange or Microsoft 365 — an extra, fully controlled layer of email security.
Inbound Relay
Point your MX record at PMG. The gateway filters every incoming message, then delivers clean mail to Microsoft Exchange on-premises or to Microsoft 365. Threats never touch the mail server — they stop at the gateway.
Outbound Relay
Configure Exchange or Microsoft 365 to relay outbound mail through PMG for policy enforcement and data loss prevention. Microsoft 365 has built-in spam filtering, but PMG adds a layer with far more granular control over how mail is classified and where it routes.
Why PIP for Proxmox Mail Gateway
Email security is only as good as the people configuring the rules. PIP designs the PMG rule set around how your business actually sends and receives mail, points your MX records correctly, sets up the relay to and from Microsoft Exchange or Microsoft 365, and tunes the spam thresholds so legitimate mail is not caught while genuine threats are. We have run mail servers and gateways on Linux since long before Proxmox Mail Gateway existed.
As an Australian Proxmox partner, PIP can supply PMG subscriptions, deploy the gateway on dedicated hardware or as a VM, integrate encrypted backup to Proxmox Backup Server, and manage the whole email security layer as part of a fully managed Proxmox environment — with first-response support in Australian business hours, not somewhere twelve time zones away. Every Proxmox Mail Gateway we run is kept patched and its rules kept current, so your email stays secure as the threats against it evolve.
Deployment, Subscriptions and Support
PIP deploys Proxmox Mail Gateway on dedicated hardware or as a VM, sized for your message volume and positioned so PMG stays reachable even during an outage of the internal server. We configure MX records, inbound and outbound relay, TLS, and the spam filtering thresholds, then validate that legitimate email flows while threats do not. Every deployment is built to keep email secure in transit and at rest, with encrypted backup to Proxmox Backup Server.
As an Australian Proxmox partner, PIP supplies Proxmox Mail Gateway subscriptions for the enterprise repository and Proxmox vendor support, and can fold PMG into a managed service plan. The result is a secure, supported platform — patched, tuned and monitored by engineers who keep it secure, not a box you install once and forget.
“The shared mailbox quarantine issue is more common than people expect. You have a support@ address shared by four or five people, all with access to the quarantine, and no way to signal who has already reviewed what — so you get duplicated effort and the occasional misrelease. The mark-as-seen feature in PMG 9.1 is a small UX change that removes a genuinely annoying operational problem. Most email security platforms at PMG’s price point — which is free — don’t think about that kind of operational detail at all.”— Brad Dixon, PIP
PIP deploys and supports Proxmox Mail Gateway.
Whether you need a fresh PMG deployment in front of Exchange or Microsoft 365, a replacement for an ageing spam filter, or subscription and support for an existing PMG installation — PIP is the Australian Proxmox partner.