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OpenDKIM

DKIM signing and verification filter for mail servers

Mail Servers ★ 118 stars Medium setup BSD-3-Clause

OpenDKIM is an open-source implementation of the DomainKeys Identified Mail standard that signs outgoing mail and verifies incoming signatures. It runs as a milter alongside Postfix or Sendmail.

Official siteSource code

Key features

  • DKIM signing and verification
  • Milter integration
  • Works with Postfix and Sendmail
  • Lightweight daemon

Strengths

  • Released under the BSD-3-Clause license
  • Written in C
  • Tiny footprint — runs in 64 MB RAM

Is OpenDKIM secure?

OSV.dev lists 2 published advisories for OpenDKIM. It doesn't publish GitHub releases we can match, so we can't say which of them apply to the current version. No known vulnerabilities is not proof of security: it means none have been publicly catalogued.

  • Most recent fixed advisory CVE-2022-48521, published 2023-07-11 (1191 days ago), fixed in 2.10.3, 2.11.0-Beta2

Source: OSV.dev, checked 2026-10-14. How this is measured.

OpenDKIM replaces

Self-hosted Proprietary email security gateways alternatives

Health badge

Maintain OpenDKIM? Add its health score to your README. The badge links back to this page.

SelfHostIndex: 60 · good

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   :alt: SelfHostIndex health score for OpenDKIM
   :target: https://selfhostindex.com/app/opendkim/

The score is recomputed on every nightly rebuild from public repository data — see how it is calculated.

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