Nebojsa Milovanovic (mail: nesha on nesha.net) - qmail stuff
This is the qmailmrtg7-4.2 patch for Tomislav Ranjdics "Force authentication on SMTP service"
I suppose that you force authentication on SMTP service only for MSA or in case that you have different qmail-smtpd instance of tcpserver for MX and SMTP and you force authentication only for SMTP.
patch < qmailmrtg7.patch
New option for qmailmrtg7 command is 'n'.
You can change log directory under the Target[authreq] in qmail.mrtg.cfg. Default is /var/log/qmail/smtpd because my opinion is that you must have separate tcpserver instance for MX and SMTP, you can block end-user IP address ranges for MX (with rblsmtpd) and for SMTP instance of tcpserver create separate SPPCONFFILE with authrequired plugin for NON RELAYCLIENT because this is good solution against spammers who try to send mails to your local users by connecting to your SMTP instance (instead of MX).