IP best?

Is cloaking by IP the best way to cloak your website? I mean, to keep a list of search engine IP's and use that to determine what to have shown. What about if a search engine gets a new IP without you knowing?

Cloaking by IP is the only way to be undetected. The search engines dont usually get new IPs, but even if they do, that one ip might not visit your site for a while.