Artica Milter is a message filter that lets you interact with messages as soon as they arrive. It is compatible with multiple SMTP instances and allows you to build rules like ACLs — and it now embeds message authentication (DKIM, ARC), greylisting and Data Loss Prevention.
This feature is available with Artica v4.50 Service pack 1 or Artica v4.50 Hotfix 20240116-15
¶ Enable the Artica Milter plugin.
- Activate the Artica Milter Plugin
The Artica milter filter must be activated in order to start writing SMTP filtering rules.
¶ Building ACLS
SMTP rules are built like a system of ACLs with which Artica Proxy edition users are familiar.
- The Power of SMTP ACLs
SMTP ACLs are similar to firewall rules. It is the same operating principle but only applies to the SMTP protocol - Rule actions: allow, log, reject, copy, tag and backup
What each core action does, when evaluation stops, and typical use cases for allow, information, discard, reject (with optional firewalling), BCC, prepend and backup. - Available objects
ACL objects for Artica Milter allow you to fine-tune your SMTP rules to filter messages. - Artica Milter and multiple SMTP instances
One milter daemon serves every Postfix instance while each instance keeps its own isolated rule set — per-instance ACLs, DKIM/ARC, greylisting and DLP.
¶ Message authentication
- Sign and verify messages with DKIM
Sign outgoing messages to protect your domain reputation and prepare DMARC. Keys are generated automatically and the DNS record to publish is displayed. - ARC sealing (Authenticated Received Chain)
Seal messages so downstream receivers can trust your authentication results even after forwarding breaks SPF or DKIM.
¶ Anti-spam
- Greylisting: defer unknown senders
Temporarily defer the first delivery attempt of unknown servers; legitimate servers retry and are remembered, most spam bots never do. SPF/DMARC-authenticated senders are never delayed. - SpamAssassin scoring in milter rules
Score each message with the SpamAssassin engine and use the score as a rule condition: tag suspicious mail, reject blatant spam — you choose the action per threshold.
¶ Data Loss Prevention
- Data Loss Prevention (DLP)
Inspect messages and attachments (ZIP, Office, OpenDocument, PDF) for credit cards, IBAN, social-security numbers, credentials or confidential keywords — then log, reject, quarantine, forward or tag the message. Ready-made templates included.
¶ Monitoring and maintenance
- Monitoring, statistics and the REST control API
Live statistics, zero-downtime policy reload, DKIM key generation and greylisting / DLP dry-run simulators on a local Unix socket. - Enable the Debug mode and export events