Proxmox Mail Gateway
Anti-spam and email security
Swiss Managed Proxmox Mail Gateway with walkingtoweb
Mail gateway against viruses
Every incoming message is scanned in real time before it reaches your inbox. The integrated ClamAV engine reliably detects malicious code in attachments and removes it before it can do any damage.
This keeps infected emails out, without additional antivirus software on every single device.
Mail gateway against trojans
Disguised malware likes to hide in harmless-looking invoices, job applications or delivery notes. Proxmox Mail Gateway analyses attachments and links in depth and stops suspicious files before a single click is enough.
Camouflage is no use here: what does not get through cannot open a back door into your network.
Mail gateway against spam
Unwanted advertising and fraud attempts cost time and nerves every day. Using several interlocking checks, the mail gateway assesses every email and reliably filters out spam – before it burdens your mail server.
What remains is exactly what really matters: your genuine business mail.
Proxmox Mail Gateway – security for your email
What is a mail gateway?
A mail gateway is the upstream security layer between the internet and your mail server – comparable to a reception desk that checks every message before it enters the building. Your MX record points to the gateway rather than directly to the server: every incoming and outgoing email first passes through this central control layer.
Here, senders, SPF / DKIM / DMARC records, content, attachments and links are analysed in fractions of a second. Wanted mail is forwarded cleanly, while spam, viruses and phishing are reliably blocked or moved to quarantine.
The advantage: all security rules are held centrally and consistently on one system – not spread across individual devices. For your staff, the gateway remains invisible; for you, it brings maximum security and less effort.
Central, reliable security for your incoming and outgoing email.
What makes Proxmox Mail Gateway better?
Proxmox Mail Gateway combines proven open-source technology with full transparency. The code is open (AGPLv3) – you always know what happens to your emails. No proprietary clouds, no hidden dependencies.
Under the bonnet, Postfix, ClamAV and SpamAssassin work together seamlessly. Filtering takes place before the queue, so unwanted emails are rejected before they consume resources.
A clean web interface, powerful message tracking and an optional cluster function ensure maximum overview and stability.
Open-source technologies without a black box for the digital sovereignty of your email.
Why should we use a gateway?
Email is the most important means of communication in everyday business – and the biggest gateway for attacks. Phishing, malware and fraud attempts hit every mailbox every day; local scanners or Outlook add-ons are no longer anywhere near enough.
A central gateway stops threats before they reach the inbox – across all devices and with little maintenance. Rules maintained once apply to all mail clients and devices; updates are carried out centrally.
At the same time, a gateway also protects outbound traffic: it prevents sensitive data from accidentally leaving the company. This protects your technology, reputation and business operations alike.
A mail gateway offers comprehensive protection against digital threats via email.
What is possible?
Proxmox Mail Gateway covers every aspect of modern email security: protection against spam, viruses, trojans and phishing, both inbound and outbound. A wide range of coordinated tests – from SPF and DNS blocklists to content and sender ratings – closes almost every loophole.
At SMTP level, the system already filters messages to non-existent recipients, considerably reducing the volume. The finely adjustable scoring system ensures precise detection with minimal false positives.
Using the rule-based control system, you define your own policies – for example by sender, recipient or content. The message tracking centre enables complete tracing of every delivery.
As a software appliance, the gateway works seamlessly with Exchange, Microsoft 365, Postfix and all common servers, as well as with the Kerio Connect groupware we offer.
The walkingtoweb Proxmox Mail Gateway can be used with any email server.
What else can the mail gateway do?
Beyond its filtering functions with mature virus protection, Proxmox Mail Gateway shines in day-to-day operation: a single server processes hundreds of domains and millions of messages every day – scalability included. If your needs grow, the system expands as a cluster, without reinstallation or downtime.
The cluster function guarantees high availability: if one node fails, the others take over automatically. Backups, encrypted on request and complemented by Proxmox Backup Server, reliably protect the configuration and quarantine.
A modern dashboard, statistics, searchable quarantine, certificate management and two-factor login ensure that you always keep track and can react quickly – instead of just repairing things after the event.
Monitor and block senders or suspicious content centrally, protecting your email server and your business.
Why is walkingtoweb the best choice?
Strong technology only shows its value through careful operation – and that is what walkingtoweb stands for. We run Proxmox Mail Gateway as a managed Swiss service on our own infrastructure. Your emails stay in the country, under Swiss data protection law – safe from third-party access.
For us, open source is everyday practice: for years we have relied on Linux- and Proxmox-based solutions rather than opaque rental models. You get setup, updates, monitoring and support from a single source – with a direct contact person who knows your environment.
In this way, we combine the transparency and cost-effectiveness of an open-source platform with the reliability of a managed Swiss operation. Let's talk about how we can secure your email communication for the long term.
walkingtoweb has been offering secure email solutions for businesses since 2007 and also takes care of DNS security for you.
Managed email security for your daily digital communication
Notes on prices
All prices are net prices per month and mailbox; for Swiss customers, statutory VAT will be added to the invoice. EUR / USD prices are for information only; the CHF price, converted at the current daily rate, always applies.
The basic setup for the Community Edition of Proxmox Mail Gateway is charged as a one-off fee of CHF 50. We will be happy to quote for further services or other subscriptions on request.
Our General Terms and Conditions apply.
This price list is valid from 1 July 2026.
FAQ
Frequently asked questions
For further questions and clarification about the functions and possibilities of Proxmox Mail Gateway, please feel free to contact us.
-
What counts as a mailbox?
A mailbox corresponds to an account with which you log in to the email server. If you have set up additional alias email addresses for this mailbox, these are not charged separately.
-
What is SPF?
Sender Policy Framework (SPF) is an open standard for validating emails and preventing sender IP address spoofing. With SPF, the administrator of an internet domain can specify which computers are authorised to send emails for a particular domain. To do this, a specific SPF record is created in the Domain Name System (DNS).
-
What is a DNS blocklist?
A DNS-based blackhole list (DNSBL) is a method by which a website can publish a list of IP addresses. The format can easily be queried over the internet by computer programs. The technology is based on the Domain Name System. DNSBLs are used to publish lists of addresses associated with spam.
-
What are block lists and welcome lists?
Block lists and welcome lists are an access control mechanism for accepting, blocking or quarantining emails from senders. This approach makes it possible to fine-tune the rule system by applying various objects such as domains, email addresses, specific expressions, IP networks, LDAP groups and others.
-
What is a Spam URI Realtime BlockList (SURBL)?
SURBLs are used to detect spam based on URIs in the message body (usually websites). This distinguishes them from most other real-time blocklists, because they are not used to block spammers. Instead, SURBLs make it possible to block messages that contain spam hosts in the message body.
-
What is an SMTP whitelist?
Senders can be excluded from SMTP blocking. To bypass all SMTP checks (such as greylisting, receiver verification, SPF or RBL) and to accept all emails for analysis in the filter rule system, the following can be added to the list:
domains (sender/recipient), mail address (sender/recipient), regular expression (sender/recipient), IP address (sender), IP network (sender). -
What is greylisting?
"Greylisting" an email from a sender that your system does not recognise means that it is temporarily rejected. As temporary failures are built into the RFC specifications for mail delivery, a legitimate server will try to deliver the email again later. This is an effective method because spammers do not retry delivery. Greylisting can reduce your email traffic by up to 50%. An email that is on the greylist never reaches your email server. This saves your email server from sending useless "non-delivery reports" to spammers.
-
Can I adjust the rules myself?
With a private Proxmox Mail Gateway, you have full access to the administration of the object-oriented rule system. This allows you to define all rules yourself according to various categories (From, To, What, When) and fine-tune them to your requirements.
-
Can the mail gateway also be used with other email servers?
Yes, the mail gateway can also filter emails that are hosted with another email provider.
An additional MX record must be added in the DNS for the mail gateway so that all emails are first sent to the gateway. Once the emails have been checked, the mail gateway forwards them to the actual email server. -
How am I informed about rejected emails?
Once a day, the gateway sends a status email (Daily Spam Report) for each email address, listing all blocked emails. Here you can choose whether an email should be delivered, or whether you want to allow the sender in general (whitelist) or block them in general (blacklist).
You can also change these settings later in the web interface.
More smart cloud solutions from walkingtoweb
Business email with Kerio Connect
Reliable email groupware
Details & VergleichMake your email secure
Comprehensive support to secure your email
Details & VergleichMatomo Analytics
See how successful your website is
Details & Vergleich
