[Mimedefang] filter_relay

David F. Skoll dfs at roaringpenguin.com
Fri Oct 29 21:41:44 EDT 2004


On Fri, 29 Oct 2004, David Hiebert wrote:

> My second question/problem is the 3 commented out lines.  The man page for
> mimedefang-filter indicates that if an IP has no reverse dns, then
> $hostname is a duplicate of $hostip.  This then should make a real quick
> and easy check for no reverse, however the if statement (when not
> commented) never seems to be true.

My mistake, the man page is wrong.  If $hostip is 1.2.3.4 and has no
reverse DNS lookup, then $hostname is [1.2.3.4].  That is:

	if ($hostname eq "[$hostip]") {
		# You have no reverse DNS!!!!
	}

However, I question the wisdom of rejecting mail from machines with no
reverse DNS.  I'm not convinced it will block bad mail more often than
good.

--
David.



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