Yahoo Developing Open Source Server Software For Spam-Resista nt E-Mail

Julian Field mailscanner at
Mon Dec 15 17:38:48 GMT 2003

At 16:42 15/12/2003, you wrote:
> > -----Original Message-----
> > From: Julian Field [mailto:mailscanner at ECS.SOTON.AC.UK]
> > Sent: Saturday, December 13, 2003 5:14 AM
> > Subject: Re: Yahoo Developing Open Source Server Software For
> > Spam-Resista nt E-Mail
> >
> >
> > At 17:45 12/12/2003, you wrote:
> > >Furnish, Trever G wrote:
> > >>I for one would be quite willing to consider the ability to
> > send email as
> > >>domains you aren't authoritative for as a casualty of war.
> >
> > I think all of the (possibly millions) of people around the
> > world who own a
> > domain while not owning an outgoing mail server would disagree.
>I am operating under the assumption that if you own a domain,
>then you will have the authority and capability to control
>which servers are designated as mail senders within your domain,
>even if your domain is hosted by an ISP.  You seem to be making
>the exact opposite assumption (and you may be right, given that
>I've seen no technical details on this implementation).

Your assumption is fine for little ISPs. But what about the Yahoos and AOLs
of this world? They would have to manage thousands and thousands of domains
for their customers. They are also using dynamic IP allocation, so they
would have to allow all their IP addresses to send mail as coming from any
customer-owned domain name.

So user1 has "" and user2 is a spammer. User2 can send mail
from "" and there's not much you can do to stop him. The only
chance is to change all the DNS records, saying who can send what from
where, every time a user logs in and logs out. Impossible.

I have yet to see any solution to this problem which
(a) actually works, even in theory (most are based on broken logic)
(b) scales to large ISPs

>Not allowing for such a set-up would indeed make such a system
>next to worthless.  Again though, more technical details on the
>implementation are needed.

Julian Field
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