[SPAM-TAG] Re: [SURBL-Discuss] A list of spammers urls

[Jeff Chan]

On Monday, March 14, 2005, 5:03:31 PM, Matthew Eerde wrote:
> Jeff Chan wrote:
>> On Friday, March 11, 2005, 2:30:05 PM, Matthew Eerde wrote:
>>> Jeff Chan wrote:
>>>> On Friday, March 11, 2005, 4:33:45 AM, Chris Edwards wrote:
>>>>> I wonder if there'd be much mileage in a SpamAssaassin feature to
>>>>> award points for any URLs that don't resolve ?
>>>> 
>>>> In principle it's something that could be done, but the timeouts
>>>> encountered trying to resolve non-existent domains could make it
>>>> impractical.
>> 
>>> Aren't the name resolution attempts done in parallel?
>> 
>> Even if they are, there needs to be a reasonable timeout on
>> resolution set, like 10 seconds.  That may not seem like a very
>> long delay, but it can keep open server memory allocations, etc.

> I see your point.

> "No such domain" and "no such entry at this domain" responses
> are very fast, though.  Couldn't at least quick negative
> responses be worth points?  Could use a timeout of one or two
> seconds to save 
> server resources - with a timeout not being worth points at all.

Yes, assuming the additional checks network-wide didn't slow down
the root name servers.  Scalability should be considered.

  http://www.caida.org/projects/dns-analysis/index.xml
  http://www.nanog.org/mtg-0210/ppt/duane.pdf
  http://dns.measurement-factory.com/tools/dnstop/

Jeff C.
--
"If it appears in hams, then don't list it."