On Sat, Jul 05, 2003 at 10:43:21AM -0400, Ken Hirsch wrote
From: "Walter Dnes" <waltdnes(_at_)waltdnes(_dot_)org>
Everybody starts off presumed innocent until listed in a DNSbl, which
takes care of your worry about new/unknown servers.
That's rather the opposite of what I meant. It is necessary that
new and unknown servers be presumed guilty. That's one of the main
problems with blacklists.
There are thousands of new open relays and open proxies created
each week. A virus could create hundreds of thousands in a day.
Blacklists can't cope with that.
Start off with DNSbls listing dynamic IP address *RANGES* (e.g. CIDRs)
and you'll have most of today's proxy problem licked. Actually, blocking
all non-static IP address ranges does converge to your proposal of white
listing "valid" mail servers.
--
Walter Dnes <waltdnes(_at_)waltdnes(_dot_)org>
Email users are divided into two classes;
1) Those who have effective spam-blocking
2) Those who wish they did
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