Warning: /etc/postfix/main.cf: support for parameter "smtp_use_tls" will be removed;

[ANofsinger-Leer]

...
Setting configuration option message_size_limit with value: 40960000
/usr/sbin/postconf: warning: /etc/postfix/main.cf: support for parameter "smtp_use_tls" will be removed; instead, specify "smtp_tls_security_level"
postfix/postlog: starting the Postfix mail system
...

I see this warning in the log files everytime the container starts now. Thought I should mention it.

[juanluisbaptiste]

Hi @ANofsinger-Leer, I suppose it will go away when Alpine updates Postfix to a version that does not include that parameter. We don't add our own main.cf file; instead, we modify it on the fly at container startup with the configurations from the environment files we support.

[juanluisbaptiste]

Reopening, we DO modify those lines with the MESSAGE_SIZE_LIMIT variable, so we will need to update that code to use the new option.

Thanks for reporting.

[barry-luijten]

@juanluisbaptiste: the option smtp_use_tls is also set explicitly here
The new option smtp_tls_security_level is also set, but only when SMTP_PORT equals 465. My relay uses 587, so this setting is not applied in my container.

[juanluisbaptiste]

@barry-luijten yes, I misunderstood the log posted by @ANofsinger-Leer and the variable to modify is the one you show. I'm looking at the documentation to understand what's the equivalent of smtp_use_tls = yes with smtp_tls_security_level.

[nomoon]

Looking at https://www.postfix.org/postconf.5.html#smtp_use_tls and https://www.postfix.org/postconf.5.html#smtp_tls_security_level, it looks like smtp_use_tls = yes is equivalent to smtp_tls_security_level = may (opportunistic TLS with fallback to plaintext, which modern SMTP servers might refuse these days even on port 587). smtp_tls_security_level = encrypt will make TLS mandatory, as would be expected on port 465.