An alternative to the question of 1U colo for this purpose is simply purchasing authenticated SMTP service. With the blocking of DSL/etc netblocks being more and more common, they're popping up everywhere, both with and without decent abuse desks. I'm biased, of course, since I /am/ the abuse desk for ours, but it's out there, and it's $14.95/year for 150 relays per day. See http://www.dyndns.org/services/mailhop/outbound/ for details of our service that does this - plenty of other DDNS providers have been adding their own, as well as more "normal" mail players. It's likely to be cheaper than a 1U server colo'd somewhere, if you're using that server exclusively for SMTP relay, and it doesn't require as much SMTP clue to set up properly. And at least in our case, we make darned sure that our servers don't get abused, and thus don't get stuck on blacklists. Tim Wilde -- Tim Wilde twilde@dyndns.org Systems Administrator Dynamic Network Services, Inc. http://www.dyndns.org/