[SURBL-Discuss] important reduce wrise renkles & skin spots ( fwd)

Joe Wein joewein at pobox.com
Wed Sep 15 10:13:57 CEST 2004

Alex Broens wrote:
> > What is your expiration algorithm?
> None so far. As its all very new, I'm still "collecting".
> On my local IP RBL I have 30 days, dunno yet what to use on URIs, I
> assume that using 6 months at least would be  safe.
> Suggestions?

In my spamfilter I keep a "referenced" list of domains: Every time I have a
positive lookup and the domain is not in the referenced list, I add it.

Then every couple of weeks I rename the referenced list file and start from
scratch. By intersecting these limited timeframe usage lists with the larger
blacklist I can later verify which domains were actively spamvertised during
what period.

So I could do someting like remove all entries added to the local blacklist
list between January and April that were not advertised between May and
August, for example.

If we had activity data for how many times the DNS server returned a hit for
which domains on a given day, we could also work out such heuristics.


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