spamd review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

spamd is OpenBSD’s spam deferral daemon for SMTP traffic, intended for administrators operating mail infrastructure on OpenBSD. It is free and open source, and runs self-hosted rather than as a hosted mail-filtering service. Greylisting is its central job: previously unseen sending hosts receive temporary failures, while whitelisted hosts bypass the daemon and continue to the real mail server. That makes it a fit for admins who want direct control over SMTP connection handling, not a general-purpose security suite.

Its policy controls extend beyond greylisting. Administrators can handle blacklists and whitelists, choose blacklist-only operation, configure greylisting expiration timers, and load blacklist databases through spamd-setup. Spamtraps and greytrapping add ways to identify unwanted sending hosts. Tarpitting and stuttered SMTP responses can slow connections, while syslog connection and message logging give operators records to review. Multiple spamd daemons can synchronize spam databases, which is relevant where mail infrastructure has more than one instance.

The tradeoff is a deliberately narrow scope. spamd’s listed capabilities focus on deferral, rejection, and SMTP-level policy; they do not cover phishing or malware detection, quarantine, or broader message filtering. It is therefore better suited to operators who can manage OpenBSD mail infrastructure and want a lightweight layer of connection controls than to teams seeking a comprehensive filtering product. Choose another category of tool if you need those broader protections or a hosted service. Documentation is the stated support channel.

spamd pros and cons

• Where it wins
  • Defers previously unseen SMTP hosts with configurable greylisting timers.
  • Supports blacklist and whitelist policies, spamtraps, and greytrapping.
  • Can tarp it connections and synchronize spam databases between daemons.
• Where it doesn't
  • Focused on SMTP connection controls rather than broader spam filtering.
  • Requires self-hosted deployment in an OpenBSD mail environment.
  • Documentation is the listed support channel.

spamd fact sheet, pricing and score →

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Last updated 7 Oct 2026 · How we research and update