Autor: Exim Mailing List Data: A: exim-users Assumpte: Re: [exim] Default enabling of dnsdb
On Sun, May 10, 2009 at 02:37:20AM +0800, W B Hacker wrote: > Brian Blood wrote:
> I get the impression those participating in the thread are not aware
> that the Exim reverse_host_lookup has sufficiently thorough logic to
> discriminate between 'good enough' and 'NFW' returns.
Neither reverse_host_lookup or the $host_lookup_failed variables are
acceptable for testing explicitly for the existance of PTR records.
Both will fail if the forward lookup fails.
Also, those mechanisms do not give enough granularity over DNS
timeouts on *just* the PTR lookup itself. The $host_lookup_deferred
will be set if either the PTR or the forward lookup times out, which
compounds the problem further.
I am unaware of any other way to do this without using dnsdb.
