Jozsef Kadlecsik:
> > How persistent are dynamic DNS updates? If the DNS server throws away
> > information after a few hours, then it is no good as a cache. You'd be
> > better of with memcached.
>
> Those are persistent and not deleted automatically by the DNS server.
Postscreen does DNSXL lookups in parallel, and they make take several
seconds to complete, so the occasional delay or lost packet does
not adversely impact postscreen's performance.
Postscreen database updates must be fast because they are synchronous.
With dynamic DNS, any delay or lost packet must not cause postscreen
to grind to a halt.
Either one would have to make the Postfix table infrastructure
asynchronous, or one would have to implement a new caching daemon
that completes dynamic DNS updates in the background. proxymap is
not such a program.
Wietse
