If one IP is suspect, well, then they must all be.
A message you sent could not be delivered to some or all of its recipients. The following addresses were undeliverable: fakelocalpart@hotmail.com: 5.7.1 Unfortunately, messages from [i.p.add.ress] weren't sent. Please contact your Internet service provider since part of their network is on our block list (AS3140). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [BFFFFFFF1FFF46.eop-nam01.prod.protection.outlook.com]
Lets all try to get along, shall we?
Mail server running from that IP for, dunno, about 8 years without issue.
Why can't you keep track of IPv4 space for your smtp blacklist needs?
Makes me suspect your ability to run bing - a web cataloging / search service :-)