In article <pan.2006.10.02.15.36.49.568374@five-ten-sg.com> Carl
Byington <carl@five-ten-sg.com> writes:
>
>On Sun, 01 Oct 2006 20:54:02 -0700, Dennis Peterson wrote:
>
>> Carl Byington wrote:
>
>>> If you don't like those "features", you could use
>>> <http://www.five-ten-sg.com/dnsbl/> which can be configured to do the
>>> same sort of thing.
>
>> It isn't obvious from reading the docs (which are spare) that this
>> product
>> does any caching of forward lookups. I consider that an essential
>> feature.
>> Multiple servers querying Exchange for the same addresses 24x7 seems a
>> bit
>> inefficient.
>
>It does not currently cache the results of the lookups, mainly because
>that feature was added to allow backup MX servers to have access to the
>valid user list

Hm? As has been pointed out before here, a backup MX server is the one
place where "SMTP-ahead" (I assume this is what is being discussed) is
less than ideal (understatement:-) - the point of having a backup MX (if
any) is that it should accept mail when the primary MX is down, and then
"SMTP-ahead" will not work...

--Per Hedeland
per@hedeland.org