Re: [Exim] Blacklisting dynamic IP ranges versus dyndns.org

Alan J. Flavell wrote:

> A topic that's come up a few times lately with us is how to accept
> mail from 'good guys' who are registered with dyndns.org when their IP
> is in a range that's otherwise blacklisted as a spam source.
>
> Sure, if we know in advance who they're going to be, we could
> whitelist them; but that wasn't my point.
>
>
Since you're using Exim 4, you can just add

! hosts = *.dyndns.org

or something similar to your ACL rule that does the DNSBL lookups. This will
keep those hosts from being looked up, but only if their reverse DNS resolves to
the dyndns.org domain. This will not take into account the HELO data supplied,
but I wouldn't want to rely on that anyway :-).