How does SASL know to read config from /etc/postfix/sasl?

Question

I've set up Postfix to authenticate with SASL on a Ubuntu based system. I've done this by following along with some recipes, but mostly readying a lot of the docs.

One bit that works, but which I don't understand how it works is based on a recipe from the postfix website. I have created the file /etc/postfix/sasl/smtpd.conf, which I understand is a SASL, not Postfix, configuration file. How does SASL know to check this location for config when working with Postfix? I didn't have to configure SASL to point to this directory, so is it hard coded? Are there any other directories will SASL search in for config?

Answer 1

Consider the image below:

following is the link for the image I have added above.

https://www.postfix.org/SASL_README.html

Please Go to the "Configuring Cyrus SASL" Section. by This postfix read all configuration files under /etc/postfix with suffix of .conf .

But to answer your question,

I didn't have to configure SASL to point to this directory, so is it hard coded

The answer is "Yes"

if you run the following command in your terminal, you may see that "smtpd_sasl_path" is equal to "smtpd" as below image:

The name of the configuration file (default: smtpd.conf) is configurable. It is a concatenation from a value that the Postfix SMTP server sends to the Cyrus SASL library, and the suffix .conf, added by Cyrus SASL.