Turn on debug mode in Postfix

There're few ways to turn on debug mode in Postfix, you can choose the one you prefer.

Verbose logging for specific SMTP connections

To debug smtp connection from particular client or sender server, list client hostname or IP address in the debug_peer_list parameter (in /etc/postfix/main.cf). For example:

debug_peer_list =

You can specify one or more hosts, domains, addresses or net/masks. Execute command postfix reload to make the change effective immediately.

Making Postfix daemon programs more verbose

There're many daemon services defined in /etc/postfix/master.cf, for example:

smtp      inet  n       -       n       -       -       smtpd

To make Postfix logging verbose info of this daemon, please append one or more -v options to selected daemon and execute command postfix reload.

smtp      inet  n       -       n       -       -       smtpd -v

See also