Security Layers

Axigen Documentation

Axigen comes with a full security feature set, guaranteeing secure reception, transit, and delivery of email, as well as protection for your confidential data.


The Axigen mail server supports authentication, meaning it can be instructed to accept only connections / messages from authenticated entities. Normal login, LOGIN, PLAIN, CRAM-MD5, DIGEST-MD5 and GSSAPI methods are available for client authentication, reducing the risk of unauthorized connections.

Encryption (SSL/TLS)

All Axigen communication protocols can benefit from SSL/TLS technology which allows sending encrypted messages across networks and preventing plain text messages to be intercepted on the way from sender to recipient. This encryption method guarantees secure data transmission over networks.

Built-in firewall (application level)

Stopping spammers and preventing DOS attacks is one of the most important tasks of a mail server and the sooner the problem is identified in the mail stream, the better. This is why Axigen has a built-in firewall at the application (TCP listener) level that allows you to control connectivity parameters, like the following listener rules:

  • maximum simultaneous connections;

  • maximum connections to be accepted during a time interval;

  • maximum simultaneous connections accepted from a single host (that may be an attacker).

Furthermore, you may define IP sets that have specific sets of such rules, applied with different priorities or IP sets whose connections are denied.

Anti-spoofing (SPF and DomainKeys compliant)

SPF authentication is used by the SMTP Incoming module in Axigen to determine whether the mail message comes from an authorized source. DomainKeys is an email authentication system designed to verify both the DNS domain of an email sender and the message integrity. This additional authentication method significantly reduces spoofing attempts (unauthorized attempts to gain server access), or assuming a fake identity when sending an email.

Message acceptance rules

You can configure and implement message acceptance policies and adjust them to best suit your company's security requirements. Incoming connections established via SMTP and the message flow can be easily managed using the established policies.

AntiVirus / AntiSpam

The Axigen mail server can easily integrate with a large number of anti-virus / anti-spam applications, either commercial, or open source.

Routing rules

The Processing policies correspond to the SMTP Processing and SMTP Outgoing modules. On one hand, they enable you to define the NDR (Non-Delivery Receipt) text and the conditions when such a message is returned. On the other hand, they allow you to customize SMTP Outgoing actions for all or part of the relayed email communication.

Message rules

Message rules instruct the Axigen mail server to take certain actions on processed email messages based on pieces of information contained by the message headers.

Country filtering

This filtering enables you to determine geographic locations based on IPs and create rules accordingly, such as banning or allowing emails sent from selected countries.

Identity Confirmation

Axigen Identity Confirmation is basically the implementation of a Challenge / Response-based anti-spam method. It blocks unwanted messages from reaching your users' Inbox by intercepting incoming emails and requiring new senders to confirm their identity, without any effort from their part.


The "Greylisting" feature enables the Axigen server to automatically reject messages from unknown senders / IPs with a temporary error message ("451 Temporary rejected by greylisting"). Unlike legitimate email servers, most spam sources will not try to resend the emails in question, thus reducing the amount of spam received by Axigen.

Find out more about how Greylisting works in this dedicated article