Catch up on the latest product updates, best practices, and expert insights from the Checkmk Conference #12 – Watch the livestream recordings now

Werk #9583: Fix missing SASL mechanism filter for PLAIN mail authentication

Component Firmware
Title Fix missing SASL mechanism filter for PLAIN mail authentication
Date Aug 17, 2026
Level Trivial Change
Class Bug Fix
Compatibility Incompatible - Manual interaction might be required
Appliance Version 1.7.23 Not yet released

Before this werk, configuring outgoing mail authentication with the "PLAIN" method did not add a smtp_sasl_mechanism_filter to the Postfix configuration, even though the user explicitly selected this method. Only the "LOGIN" method was correctly written to the configuration.

This werk fixes the "PLAIN" method to also write smtp_sasl_mechanism_filter = plain, matching the explicitly selected authentication method. Systems relying on the previous negotiated behavior when "PLAIN" was selected will now have the mechanism explicitly forced to "plain".

To the list of all Werks