src/usr.sbin/smtpd/smtp_session.c contains the following code:
1892 static void
1893 smtp_proceed_wiz(struct smtp_session *s, const char *args)
1894 {
1895 smtp_reply(s, "500 %s %s: this feature is not supported yet
;-)",
1896 esc_code(ESC_STATUS_PERMFAIL, ESC_INVALID_COMMAND),
1897 esc_description(ESC_INVALID_COMMAND));
1898 }
This was added between revisions 1.194 and 1.195, with no mention in the
changelog.
I'm not aware of a 'wiz' command in any SMTP related RFC.
Is this spurious debugging code related to the addition of DSN and enhanced
status code support? Or is it there as a way to identify servers that are
running smtpd in the wild? Or is there some other reason?
