To speed up Domain Name System records (DNS records) most name servers on the internet will cache (remember) DNS records themselves, so that they do not have to look up records each time they require them.
When you visit a website, it is probable that your ISP's name servers will remember the IP Address, so that the next time you (or someone else) requests that website, the IP address can be retrieved more quickly.
In this instance your ISP's name server is using a cached DNS record. It will use this cached record for a period of time, after which it will retrieve the record again. It will again cache the record and the cycle will repeat.
This is why when you make changes to your DNS some people will not see the change immediately as they may well be seeing a cached record.
We recommend allowing 12-24 hours for name servers around the world to delete their cached record, and request the new updated one.
You can try to clear the cache manually on your computer:
1. Go to Start > Run.
2. Type 'cmd' and click OK.
3. In the console type 'ipconfig /flushdns' and click Enter.
4. Go to http://yourdomain.com and check whether you can see your new site.
1. Open /Applications/Utils/Terminal.app
2. type sudo dscacheutil -flushcache (for Leopard) or sudo lookupd -flushcache (for Tiger)
3. Enter your system password (if required)