Proxmox Mail Gateway: keeping spam and phishing out
Most attacks start with an email. Proxmox Mail Gateway checks every incoming and outgoing message before it reaches your mail server. We run the filter in Switzerland and keep tuning the rules.
What is Proxmox Mail Gateway?
Proxmox Mail Gateway is an open-source filter that sits between the internet and your mail server. It checks senders, content and attachments, holds suspicious messages in quarantine and only lets clean mail through. It works with any mail server, whether Exchange, Microsoft 365 or Zimbra.
At a glance
- Spam, virus and phishing filter in one
- SPF, DKIM and DMARC checks
- Quarantine with a daily report for staff
- Custom rules for attachments and senders
- Operated on servers in Switzerland
Why your own filter
Less phishing
Spoofed senders, suspicious links and dangerous attachments are caught before anyone clicks.
Protection against fake invoices
Messages pretending to come from your own company or a supplier are flagged by SPF, DKIM and DMARC checks.
Full control
You see which messages were held back and can release them yourself. We adapt the rules to your business.
Independent of the mail server
The filter stays in place even if you later move from Exchange to Zimbra or Microsoft 365.
What we take care of
Setup, fine-tuning and operations from one source.
- 1
Setup
Gateway in our infrastructure in Switzerland or on your premises, MX records switched without interruption.
- 2
Email authentication
SPF, DKIM and DMARC for your domains, so your own messages arrive reliably.
- 3
Fine-tuning
Rules for industry senders, attachments and exceptions, so important mail does not get stuck.
- 4
Operations
Updates, mail queue monitoring and report analysis.
Who Proxmox Mail Gateway is right for
- SMEs with a lot of spam or phishing
- Companies running their own Exchange or Zimbra
- Businesses on Microsoft 365 that want an additional filter
- Firms that have been hit by fake invoices
Frequently asked questions
Your question is not listed? Ask us directly.
Does it work with Microsoft 365?
Yes. The gateway is placed in front of Microsoft 365 and forwards the filtered messages.
Can important messages get lost?
No. Suspicious messages go to quarantine. Staff receive a daily report and can release messages themselves.
Where are the emails checked?
On servers in Switzerland. Messages do not leave the country to be checked.
How long does the switch take?
Setup takes a few hours. We then fine-tune the rules over a few weeks.
Related insights
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- EmailNew Microsoft 365 clause: who decides about your email?Since 1 November 2026, Microsoft may pass certain Microsoft 365 content to a US reporting centre. What the clause means and when self-operated Zimbra is the better choice.Read
- IT SecurityDeepfakes and CEO fraud: when the boss on the phone isn’t the bossFraudsters use AI to imitate the voices of executives and business partners. How SMEs secure payments with call-backs and the four-eyes principle.Read
Let’s talk about Proxmox Mail Gateway.
Tell us what's bothering you. We listen, look at your situation and tell you honestly what makes sense.