API Network Corp

In order for a website to be online, it must have a full set of DNS records.  However, these records are unique based on the physical location of the server.   If you decide to move your website from one server to another, even within the same hosting company, you will also have to update your DNS records.   This update is done at the registrar, the place where your domain name is held.  (such as GoDaddy.com and enom.com)   (you do not do this where you are hosting ... although if you're hosting where you bought your name, then you would do it there)      Our recommendation:  Buy names at GoDaddy and then host at HostGator.

Changing DNS is a little different for every registrar as they have their own software to control this.   However, they are essentially all the same.   Most hosting companies will provide how-to instructions as this would easily top most any FAQ list.

After a DNS change is made, it takes from an hour to a full 24 to propagate the new information to the world.   You may notice some users will change faster than others. This is because the DNS updating process is something that can be configured by each DNS location.   Some check for updates frequently, some less frequently.   If you happen to be on a network connection that is being serviced by a fast DNS updater, then you will get to the new site more quickly than slow updaters.   Bottom line is that users can't control how quickly this happens.    (other than going to a PC at a different network connection)

Sometimes, even after the DNS has updated, a PC can "get stuck" on the old address.   A DNS entry will be cached and you will need to either flush the DNS cache to get rid of it, or wait up for it to be dropped from the cache automatically.   How long you would have to wait-- that's determined by how your DNS is configured on your PC.    Rather than trying to adjust that, the easiest way is to force a flush of the DNS cache to ensure the values are most current.

Here's how you would do this:

From a Windows PC

C:\>ipconfig /flushdns

(the C:\> means you must run CMD from the Start button to get to a DOS-looking window)

If you don't want Windows to cache your DNS, you can enter these:

C:\>net stop dnscache
C:\>sc servername stop dnscache

This will disable DNS caching until the next reboot. To make the change permanent, use the Service Controller tool or the Services tool to set the DNS Client service startup type to Disabled.

From a Mac

In Mac OSX Leopard, you can use the command dscacheutil -flushcache to flush the DNS resolver cache:
bash-2.05a$ dscacheutil -flushcache

In Mac OSX versions 10.5.1 and before, the command lookupd -flushcache performed the same task:
bash-2.05a$ lookupd -flushcache

From Linux

In Linux, the nscd daemon manages the DNS cache.
To flush the DNS cache, restart the nscd daemon.
To restart the nscd daemon, use the command /etc/init.d/nscd restart.

Under normal conditions, force a cache flush should not be required.  But, should you believe you've waited long enough and you're still pointing to the wrong server, flush it!

One last item: During a DNS change, it's possible that the new website will not be 100% functional the moment DNS changes hit.  The reason for this, which is especially true on larger/complex websites is that multiple connections to the server are being made within a page.   What you see in the title bar is only one of many connections.   If you want to explore this, run Firebug within Firebox.   It will show you all of your connections as they are made along with how long it takes to transfer each object.   A very useful tool with DNS resolution problems and just as good to see how a page might be made to load faster.