To speed up the internet, your local Internet Service Provider (ISP) caches the DNS records queried through their server. They create their own copy of the master record, and access it locally to search for website, each time someone tries to view it. This procedure speeds up the internet, reduces the traffic to the master servers and thus help ISPwork faster. Each ISP caches DNS record and update it every few days. Each ISP have there own standard time frame to update the cache DNS record. This delay from your ISP will prevent you from viewing your website. This process is know as DNS propagation delay. The slow updating of the server cache is called propagation. The DNS information for your domain gets propagated across all server’s on the web. After this propagation complete’s your website will be accessible to all. Normally the DNS propagation time may take 24 to 72 hours to be in effect.
DNS Propagation delay problem during change of hosting company
DNS propagation delay is involved in when you change web host. When you change hosting company you need to change the master dns server for your domain name. This new name servers will be found by ISP DNS servers only on the next dns cache update. Some ISPs take days to update cache. So during this time site will be inaccessible through that ISP.
First you need to try clearing Browser cache and DNS cache of your system. To clear browser cache (history) check the browsers help. After clearing browser cache close the browser. To clear DNS cache, in Windows Xp and most of other windows versions, open a command prompt. Type the command ipconfig /flushdns and press enter. This will clear DNS cache. After clearing DNS cache open the browser and try to browse your domain name again.
When the above method doesn’t solve your problem, you need to wait till the DNS cache update of your ISP. Usually 24 – 72 hrs.