"Hallam-Baker, Phillip" <pbaker(_at_)verisign(_dot_)com> wrote:
The thing I don't understand about HELO schemes is what they buy that we
would not get from simply requiring senders to give a domain name that
correctly resolves to the ip address of the sender sever.
A little more flexibility.
And pleas stop the fud about billions and billions of people, nobody has
proposed anything that affects end users. The number of mail server
operators is not billions, millions is almost certainly an overestimate.
I've managed to get some information on ip-address/volume:
http://www.striker.ottawa.on.ca/~aland/spam/sent.png
The graph plots the number of IP addresses sending non-spam traffic
at a particular volume, versus the relative volume at which they're
sending traffic. Extremely low-volume senders are not included.
A log-scale plot (with a little more detail) is at:
http://www.striker.ottawa.on.ca/~aland/spam/sent-logscale.png
This shows that there's roughly an inverse linear relationship (in a
log-log plot) between # of IP addresses and volume. e.g. 90% of the
IP addresses account for 10% of the volume.
And another view is at:
http://www.striker.ottawa.on.ca/~aland/spam/cumulative.png
This shows that any scheme which is used by the ~100K largest
senders will cover 90% of the non-spam traffic.
Alan DeKok.
