On Thu, April 30, 2015 11:14, Viktor Dukhovni wrote:
>
> Separately, various restrictions like "reject_unknown_helo_hostname"
> and "reject_unknown_sender_domain", ... use explicit DNS lookups
> that do disable the search list.
>
> Nothing to see here, the DNS queries are not unexpected.
>
I follow that. My point is that in the circumstance that a host
identifies itself solely with an IP address then the only manner in
which Postfix can obtain the associated domain name is via the PTR RR.
Since that must be, by definition, a FQDN then why is the search path
in the local resolver involved at all?
The issue to me seems to be the trailing dot on the FQDN returned from
the PRT RR which then is seemingly ignored. If the dot was retained
then the resolver, presumably, would know not to append the local
search paths, and thereby eliminate a number of pointless DNS queries
and useless log entries.
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