[SURBL-Discuss] RFC: SURBL software implemetation guidelines

Jose Marcio Martins da Cruz Jose-Marcio.Martins at ensmp.fr
Wed Apr 21 10:02:26 CEST 2004


Simon Byrnand wrote:
>>Jeff Chan wrote:
>>
>>>Good to know.  So wildcards sound like they *don't* necessarily
>>>save on DNS traffic, right?
>>
>>Right, but if one has a local AXFR or rsync of the zone, that's not an
>>issue. They DO massivly save on memory on the DNS server if you've got a
>>massive zone.
> 
> 
> Only if the wildcard is replacing multiple entries though ? Which is not
> the case with surbl.org. Here we're considering the difference between
> having one entry like:
> 
> spammer.com IN A 127.0.0.2
> 
> or one entry like:
> 
> *.spammer.com IN A 127.0.0.2
> 
> With the current approach individual randomized (or not) subdomains aren't
> being seperately listed anyway, they are stripped down and collated into
> their registrar level domain names before going into the zone files..
> (Right Jeff ?)
> 
> Same number of records, just a different representation which requires the
> client end to do the same stripping down, (slightly more work) but with
> the added bonus of much better caching on the client nameservers..

No. You need to have both records. The first will match only the domain 
itself : "spammer.com" and the second will match everything other. The 
wildcard doesn't match the domain itself. So the number of records is 
the double - but maybe I'm wrong.

It seems to me that wildcards is what spammers use to get hostname 
randomness.

But, IMHO, all this doesn't really matter. What's important is to 
optimize global delays, which are the sum of :
- DNS query handling delay
- network delay
- client query handling delay

I don't have enough data but I'll surely have some benchmarks soon. It 
seems to me that network delay is much larger than the others. So, 
probably the better way to do is that one which generates less network 
traffic.

Best,

Jose-Marcio

> 
> Regards,
> Simon
> 
> _______________________________________________
> Discuss mailing list
> Discuss at lists.surbl.org
> http://lists.surbl.org/mailman/listinfo/discuss
> 
> 



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  Jose Marcio MARTINS DA CRUZ           Tel. :(33) 01.40.51.93.41
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