Amavis is an open source content filter for electronic mail, implementing mail message transfer, decoding, some processing and checking, and interfacing with external content filters to provide protection against spam, viruses and other malware. It can be considered an interface between a mailer ( MTA, Mail Transfer Agent) and one or more content filters.
Amavis can be used to:
- detect viruses, spam, banned content types or syntax errors in mail messages
- block, tag, redirect (using sub-addressing), or forward mail depending on its content, origin or size
- quarantine (and release), or archive mail messages to files, to mailboxes, or to an SQL database
- sanitize passed messages using an external sanitizer
- generate DKIM signatures
- verify DKIM signatures and provide DKIM-based whitelisting.
- provides SNMP statistics and status monitoring using an extensive MIB with more than 300 variables
- provides structured event log in JSON format
- IPv6 protocol is supported in interfacing, and IPv6 address forms in mail header section
- properly honors per-recipient settings even in multi-recipient messages, while scanning a message only once.
- supports Internationalized Email (RFC 6530, SMTPUTF8, EAI, IDN)
A common mail filtering installation with Amavis consists of a Postfix as an MTA, SpamAssassin as a spam classifier, and ClamAV as an anti-virus protection, all running under a Unix-like operating system. Many other virus scanners (about 30) and some other spam scanners ( CRM114, DSPAM, Bogofilter) are supported too, as well as some other MTAs.