The magic plus sign

Here's an interesting log line (well I thought so)

Jun 3 20:23:13 malander sm-mta[16885]: l53JNC6x016885:
... Spam problems. Try
alan+newcontactXXXXX@clifford.ac

I have a wildcard reject on my domain, viz. "Spam problems. Try
alan+newcontactXXXXX@clifford.ac". It looks like the error message has
been parsed for an email address, the bit before the plus sign has been
stripped off, and spam sent to the remaining address.

(note that XXXXX has replaced the real text so as not to publish the
actual address here)

--
Alan

( If replying by mail, please note that all "sardines" are canned.
However, unless this a very old message, a "tuna" will swim right
through. )