[Mimedefang] Macro Built-In Defaults / _ Macro Question
David F. Skoll
dfs at roaringpenguin.com
Thu Jul 16 16:57:05 EDT 2009
Kevin A. McGrail wrote:
> I'm looking at the built-in Macros and the _ macro in the SendmailMacros
> hash looks like a possibility to replace doing a reverse lookup on
> hosts. The theory being (and someone else has mentioned this) that this
> portion of my reverse DNS check in the milter is duplicative of a
> reverse PTR lookup.
But you are already given the result of Sendmail's reverse-lookup in the
$hostname argument to filter_relay and friends, and it's in the
$RelayHostname global variable after filter_begin.
But even if you make a duplicate DNS lookup, it should be fast because
the answer is cached (you ARE running a caching DNS server, right? :-))
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