On Tue, Sep 28, 2021 at 09:50:11AM +0200, Christophe Lohr wrote: > Well.. so, my question is: how to configure postfix to be more verbose? > (not in the log files, but on the smtp connexions)
This would be a programming exercise. The relevant source files are: src/smtpd/smtpd.c - Protocol engine src/smtpd/smtpd_state.c - Connection state structure and methods src/smtpd/smtpd_chat.c - Request/Response logic You may need to record additional data in the state structure, and then emit appropriate messages when responding to the client. Most likely it is easier to just write a Perl or Python script, or Haskell or Go program that is an ESMTP server that emits detailed error messages. Choose a language in which it is easy to write a parser that emits detailed error diagnostics. It is not clear why Postfix would be a compelling choice of an an SMTP server for students new to network protocols looking for verbose error messages. -- Viktor.