Raymond Keller wrote:
I configured reject_invalid_helo_hostname and was surprised to find
that underscores were permitted. Judging by the source (I'm not
conversant in C), it looks like the author had this comment
regarding allowing underscores: "grr.." I feel similarly. Is that
you, Mr. Venema? My sympathy. I take it that allowing underscores
is for the sake of handling Windows MUAs?
windows is not the root of all evil! Underscore is actually more
unix-ish. don't forget that system hostnames predate such restrictions.
as for "funny" helo's, here is my winner:
reject: ... helo=<{bot_hostname}>
and the second price:
reject: ... helo=<zkkj.%RA.%RA.%RA.%RA.%_8%.com>
someone got a ratware but didn't pay for the "expand vars" option :)
