Author: Mike Cardwell Date: To: exim users Subject: Re: [exim] Preventing TXT lookups after successful acl modifier
dnslists processing
Mar Matthias Darin wrote:
>> Instead of using "dnslists", you could perhaps use the dnsdb lookup type
>> as a workaround. Example
>>
>> REVERSE_SENDER_IP =
>> ${sg{$sender_host_address}{\N^(\d+)\.(\d+)\.(\d+)\.(\d+)$\N}{\$4\.\$3\.\$2\.\$1}}
>>
>> That creates a macro which returns $sender_host_address with the octets
>> reversed. Then do:
>>
>> condition = ${lookup
>> dnsdb{defer_never,REVERSE_SENDER_IP.zen.spamhaus.org}{true}{false}}
>>
>> This is equivalent to:
>>
>> dnslists = zen.spamhaus.org
>
> DynaStop does this automatically and returns a code (a code 2) just for
> non-reversible domains (RDN). The results are cached generating a big
> saving in DNS queries and bandwith. I average 80% cache hit ratio from
> DynaStop (YMMW though). DynaStop can alternatively greylist non-RDNs for
> any given period if prefered.
Doesn't using DynaStop involve calling an external executable using
${run} which reads several flat files and uses up IPC shared memory in
order to obtain relatively stale results?
In what regard does DynaStop provide any advantage over using a plain
dnsbl? The guy is trying to reduce the time exim processes run, not
increase them...
