On Wed, 11 Aug 2010, Steve Atkins wrote:
Spam filtering appliances and services sometimes run as, effectively,
proxies rather than store-and-forward MTAs. Postini works in this
way, I think, as do some of the enterprise filtering appliances that
people protect their Exchange servers with.
GNU SAUCE works this way and dates from 1997 so the approach isn't that
new :-)
A key difference is that they never have to fan-out deliveries and they
have operational control over the destination, so deployments should be
able to keep a fair grip on delays.
Tony.
--
f.anthony.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
FISHER: SOUTHWEST 3 OR 4, BACKING EAST 4 OR 5. SLIGHT. SHOWERS. GOOD.