BLOCKRELAYPROBE

Rejects recipients with and "!", "%" or double-"@".

Default:

off

Affects:

qmail-smtpd

Example:

"" (any value will do)

Note:

This is quite useful to stop so called anti-spam probes of clueless and overzealus wannabe RBL operators.
These probes try to exploit some ancient sendwhale bugs never existent in qmail. Unfortunatly qmail accepts such stuff even if it doesn't relays it and bounces it later.
"!" is the old UUCP bang path.
"%" is a sendwhale relaying hack and
double-"@" a sendwhale bug.
Beware if you actually use the qmail percent-hack! Then this can't be used obviously!