smtp_tls_security_level reference
A Postfix main.cf parameter that controls identity, routing, security, queueing or delivery behavior.
Purpose
A Postfix main.cf parameter that controls identity, routing, security, queueing or delivery behavior.
Syntax
smtp_tls_security_level = valueIllustrative example
# /etc/postfix/main.cf
smtp_tls_security_level = VALUE
postfix check
systemctl reload postfixVersion-sensitive: Replace VALUE with a setting appropriate to your topology. Verify exact syntax, scope and defaults against the documentation for the installed version.
Production guidance
- Change one variable at a time
- Document the reason for the value
- Test effective behavior, not only parser acceptance
- Monitor delivery responses after deployment
- Keep a rollback copy
Common mistakes
Common failures include using the directive in the wrong scope, copying syntax from another software version, referencing an undefined object, choosing a value that conflicts with provider signals, or reloading without validation.