Thus spake Steve Snyder (swsnyder@snydernet.net):
Got another threatening e-mail from my ISP today, prompted by another SpamCop complaint regarding spam run through HotMail. HotMail records the address of the originating server and that, again, is my exit node.
So I have to curtail exit access to HotMail. Yeah, it sucks, but I know of no way to block the sending of webmail while still allowing it to be retrieved.
Make sure this is done via exit policy and not iptables or DNS filter.
Also, are you sure you have the whole hotmail netblock?