MIMEDefang
MIMEDefang: A self-hosted framework for admins who want configurable control over mail filtering. Ranked #13 of 17 in Anti-spam Software by our editors (6.8/10); pricing: Free plan; best for admins building custom self-hosted mail filters.
At a glance
- Editor score6.8 / 10
- PricingFree plan
- Best forAdmins building custom self-hosted mail filters
- Free planYes
- Paid fromFree
- Facts checked24 Sep 2026
Where it wins
- Inspects and modifies messages and attachments through Perl callbacks
- Integrates with SpamAssassin and antivirus scanners such as ClamAV
- Supports quarantine and administrative review workflows
Where it doesn't
- Requires a self-hosted mail gateway rather than hosted mailbox protection
- Filtering behavior depends on administrator-configured Perl callbacks
- Its mail-server integrations focus on Sendmail and Postfix
Our verdict on MIMEDefang
MIMEDefang is an open-source mail-filtering framework for administrators running self-hosted mail gateways with Sendmail or Postfix. It provides a way to inspect and modify messages and attachments, apply filtering policy through configurable Perl callbacks, and manage quarantine and administrative review. Its fit is strongest for teams that want direct control over mail handling and are prepared to configure and maintain their own filtering environment, rather than buyers looking for hosted mailbox protection.
The framework's breadth comes from connecting message handling with external scanners and mail-server components. MIMEDefang integrates with SpamAssassin and antivirus scanners, including ClamAV, and can modify headers and message bodies. Those capabilities let an administrator shape filtering around local requirements and route suspicious mail into review workflows. This makes it more adaptable than a narrow spam-only filter, but that flexibility rests on custom callback configuration; teams seeking a ready-to-run service with managed policies should consider a hosted alternative.
MIMEDefang is distributed as free, open-source software for self-hosted deployment, so there are no paid tiers described here to compare. The operational tradeoff is that the organization must provide and administer the mail gateway and configure how callbacks, scanners, and quarantine behave. Support channels are documentation and community, which suits teams comfortable consulting project resources but may be less appropriate for buyers who require vendor-led support. Choose MIMEDefang when Sendmail or Postfix integration and policy control matter; look elsewhere if hosted protection or a managed setup is the priority.
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MIMEDefang pricing
MIMEDefang fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Phishing protection | Not verified |
| Malware scanning | Yes |
| Quarantine controls | Yes |
| Deployment | On-premises |
| Users included | Not verified |
| API access | Not verified |
| Email continuity | Not verified |
| Deployment | Self-hosted |
| Platforms | Linux |
| Support | Docs, Community |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 4 integrations: Sendmail, Postfix, SpamAssassin, ClamAV |
| Pricing | Free plan |
| Website | mimedefang.org |
| Facts checked | 24 Sep 2026 |
MIMEDefang integrations
MIMEDefang lists 4 integrations on its own site.
- Sendmail
- Postfix
- SpamAssassin
- ClamAV
Alternatives to MIMEDefang
- RspamdConfigurable gateway filtering with machine learning and broad mail-server integration.9.1
- Apache SpamAssassinA configurable, self-hosted filter for teams managing their own mail infrastructure.8.8
- SpamTitan GatewayA gateway filter combining multilayer spam checks, sandboxing, and outbound scanning.8.7
See all MIMEDefang alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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