On Wed, 06 Jul 2011 08:15:47 +0200 Andrzej Adam Filip <andrzej.fi...@gmail.com> wrote:
> It may improve performance e.g. in case of hundredths mail servers in > a data/co-location center using shared forwarder and rejecting on > first DNSBL hit. Somehow I doubt buying data for such "reseller" > configuration is legally encouraged by paid DNSBL operators. This is true. But it's also not in paid DNSBL operators interest to improve the hit ratio. If the cache hit ratio is improved too much, the DNSBL operators would be unable to detect heavy users and ask (threaten) them for money. :) In the limiting case, if the cache becomes *too* effective, the organization hosting the cache *is* effectively providing the whole data set to its users. Regards, David.