On Fri, Feb 29, 2008 at 09:07:55AM -0600, Matt wrote:
> > >> I have this to block connections with no reverse DNS:
> > >> # : no reverse dns
> > >> #defer !verify     = reverse_host_lookup
> > >> #      message     = Reverse DNS lookup failed for host 
> > >> $sender_host_address
> 
> > And rejecting based on missing reverse DNS has way too much false
> > positives.
> 
> reverse_host_lookup seems to check if there is reverse DNS and also
> that it has a matching forward DNS.  Is there a way to only check for
> reverse and not check that there is a matching forward?  All my false
> positives seem to have a reverse DNS but the forward does not match.

Yes, but not directly through the built-in "reverse_host_lookup" ACL 
parameter since it does the forward check automatically.

Here is the equivalent ACL you could use based upon your example:

   defer
      !condition = ${lookup dnsdb{defer_never,ptr=$sender_host_address}{yes}}
      message    = Reverse DNS lookup failed for host $sender_host_address

--
Dean Brooks
[EMAIL PROTECTED]

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