rblsmtpd(1) on Linux
The text c2fbe38a2c34, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster) shipped it. The page shows this text now.
blocks mail from RBL-listed sites. It works with any SMTP server that can run under tcpserver(1)
Flags it lists
-
-B -
-C -
-a -
-b -
-c -
-r -
-t