s/qmail/DOC/rblsmtpdについて、ここに記述してください。

https://www.fehcom.de/ipnet/ucspi-tcp6/rblsmtpd.html

rblsmtpd - block mail from RBL-listed sites and unwanted sources

• Interrogation Mode

rblsmtpd may be used to only query RBLs and to present the results to qmail-smtpd in an interrogation mode.

• -i interrogation mode; the RBL information is written on descriptor 2 and available via RBLSMTPD for further decisions.

Greetdelay Options

7.6 Greylisting in qmail-smtpd