[SideshowBob]

It's actually quite common for ISP dynamic addresses to be in blocklists. It usually creates no problems unless you do something odd like trying to deliver direct-to-MX.

Which lists are you in? The fact that you have had the same address for years and are getting relisted suggests you may be running some malware or have some sort of abusable server software such as an open relay. The type of list may give some indication.