"I hate to move a website to another server, but in real life there are many situations were this will happen (maybe you need to upgrade your current server to a better one, maybe your current server is on a bad datacenter, or you just found a better financial deal, or maybe you only need to change the IPs on the same server, etc.). Besides some other problems that might appear (for example software incompatibilities, and the site not running the same way on the new server), the major problem you might face is the DNS caching problem. This means that based on what your current DNS configurations, for a period of time your site will be accessible on both servers. Now this might be ok, but in most situations it is not. For example you will have the emails delivered by some remote servers to either server, or some users browsing your site still on the old server (causing problems with e-commerce sites, or sites that depend on the various data that is saved while users browse the site). I have completed successfully with minimum downtime many such moves and I will show you how this can be done with a very simple DNS trick..."
