I'm having a similar problem with hotmail currently, although hotmail seems to have firewalled our source IP (can't even connect) anymore, and the various conta

I'm having a similar problem with hotmail currently, although hotmail seems to have firewalled our source IP (can't even connect) anymore, and the various contacts we have at Microsoft/hotmail can't even acknowledge that they are blocking a certain IP range, and keep making us run around asking us to "try connecting with telnet" (how do they think I've been verifying that one IP is blocked and other isn't?) and what our email client settings are, and how we've configured Exchange. And yes, reverse DNS is proper, as is SPF, and we've had this IP for years and hotmail has accepted mail from it in the past, and hotmail correctly accepts and delivers mail when sent from another IP. I don't mind the blocking, I recognize that as a legit way of controlling access, but what is really frustrating is that the hotmail folks assume that I don't know anything about email and that they can't even acknowledge that they have a certain IP blocked. If they could just say "Yes, we've blocked that, and there's nothing you can do or say to get us to unblock it", then we could move on; but when it looks like no one at hotmail knows what's going on, everyone continuously believes that if they just say the magic words or contact the right person, it can all be cleared up.