Re: outbound failure limiting - the next phase in the spam war?

mouss wrote:

> If ISPs were to collaborate, then let'em just give us a simple way to
> determine whether a client is "dynamic/home", "dynamic/business",
> "static/customer" or "isp". with these, we can decide whether to accept
> or not. if they block 25, we get a single IP, and we need to count on
> the ISP to manage the spam, which may be good if the ISP is good, but I
> just can't trust that.

As you note, part of the problem is that some ISPs have designated
blocks as dynamic, but allocate static IPs from the same pool for
business customers.

It would be interesting if ISPs took an active role in maintaining RBLs
that list residential or other IP addresses that should not be running a
mail server (and especially kind if they allowed users of static IP
addresses to "register" mail servers so they may be removed from the
list). This might work better than the more broad categorizations that
you suggest above (a good idea, nonetheless).

Of course, one could take this a step further and create a list
containing only IP addresses of "registered" mail servers. I don't think
it would be useful for outright blocking or whitelisting, but it might
have value in a scoring system. Certain criteria would have to be met,
and there would need to be a mechanism to remove abusive hosts
(including checking for their presence on appropriate RBLs). I have to
think the resulting list would be much smaller than any list of dynamic
IPs, and possibly easier to maintain because it removes a lot of guesswork.