Re: marking dynamic ranges, was fixing insecure email infrastructure

["J.D. Falk" <jdfalk () cybernothing org>]

On 01/25/05, Markus Stumpf <maex-lists-nanog () Space Net> wrote: 

> I am generalizing on what I see from about 300 mailservers and about
> 1 million messages a day.

        One million ain't much by today's standards.  That gets lost in
        the noise at any of the bigger providers.  I'd question whether
        that gives you a sufficiently wide sample.

        (I'm also surprised you need 300 servers to handle such a small
        load -- what is that, ~3333 messages per server per day?)

> As you can see, we don't filter out "no revDNS", too. But setting
> MTAMARK records would give the admins of the receiving mailservers
> a hint as how to classify the sending IP.

        Sure!  It's a great idea...but if you could get every site in
        the world to cooperate on ANY great idea, we'd be way ahead.

-- 
J.D. Falk                                          uncertainty is only a virtue
<jdfalk () cybernothing org>                    when you don't know the answer yet