smtpprox-loopprevent(1) on Linux
The text f374381c21fa, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it. The page shows this text now.
Transparent SMTP proxy to prevent mail forwarding loops
Flags it lists
-
--children -
--debugtrace -
--maxperchild -
--minperchild