• filter spamtrap
  • filter spf
    •

    OpenSMTPD SPF filter

    OpenSMTPD filter to enforce the Sender Policy Framework.

    Changelog

    v1.0.1 - 2026-08-11
    v1.0.0 - 2025-10-27

    v0.5.0 - 2024-09-18

    Build

    Go >= 1.22 is required.

    git clone https://netsend.nl/opensmtpd-filter-spf.git
cd opensmtpd-filter-spf
go build

    Install

    Execute the following as the superuser. 
    install -m555 -gbin filter-spf /usr/local/libexec/smtpd/
useradd -d /var/empty -s /sbin/nologin _spf
    Define the filter and add it to your listen directives.

    smtpd.conf:

    filter "spf" proc-exec "filter-spf" user _spf
listen on egress filter { spf }

    Code and repository

    Browse the source code here or on GitHub or clone the repository:

    $ git clone https://netsend.nl/opensmtpd-filter-spf.git