I have a few static IP Addresses I pay monthly for from my DSL ISP. I run web servers on the IP Addresses, and do some hosting for a couple small sites. The ISP charges me $10 a month per IP Address, and they do not offer any package plan. So that kinda sucks.

Well, the other day my friend mentioned he needed web space and wanted to know if he could pay for a static IP Address for us to host. Then he asked if he bought an IP Address from another ISP, if he could just use that one on our servers. He insisted that it is easy to do and wouldn't require reconfiguring our network at all. That comment confused me. I have never done anything like that, nor have any clue how I would go about setting that up on the servers.

Is that even possible? Purchasing IP Addresses from another ISP, and have a server using not only the assigned IP Addresses from it's own ISP, but also using other IP Addresses bought from a different provider? If that is possible, I am thinking about finding a place that would sell IP Addresses for cheaper than the $10 / month now I get charged. But I have never heard of doing that, and am wondering if it is even possible.

Any info appreciated. Thanks.