I think pretty much everyone understand WHY people use these BLs. This
is not the point. The point is, its not a very good solution.
Is it even a solution? I guess that depends o nwhat the problem is. If the problem is the volume of mail passing through the servers then I suppose it is. The ultimate extrapolation of this is that in a perfect world no mail would be allowed to pass through so that we can continue to run our servers on 286s!
Maybe I'm being naive but I thought the objectives were not to make live easier for the mail administrator (though that would be nice) but to ensure that the people who actually run the business (accountants, sales staff, support engineers, CEOs, etc.) receive all relevant mail that is sent to them and don't have to waste inordinate amounts of time wading through spam. I see the first of these as being of signifcantly more importance than the second.
Blocking on content achieves the second of these, sorry if it now requires more car and attention to keep that server running. Blocking on the source IP address, purely because it may be dynamic or may have sent spam some time in the past makes the first objective virtually impossible to achieve.
Unless the spam vigilante sends a notification to the intended recipient of every mail it has blocked so that they can check if this should have been the action taken. This sort of defeats the second objective.
I am not against DNSBLs. What I would like to see is more honesty in how they should they used. They are a tool, not a solution. Their web pages should have a warning liek cigarette packs 'use of this service to block rather than score emails can cause blindness, madness and bubonic plague'. Too many of our users' destinations seem to be using these sites as though they are infallible.
Since it is the sender who is notified of the bounce, by our mail server, not the recipient (who unknowingly sanctioned it) the problem is placed at our doorstep to resolve.
mike
