How DNS works
When you create a hosting account with a web hosting company, a Master DNS Record is created in the Internet Service Provider's (ISP's) Domain Name Server (DNS).
The registrar from whom you have purchased your domain refers to this DNS Record as the master authority for the domain used by your hosting account.
When someone searches for your website at the domain, their browser request is taken:
- first, to the registrar's database to discover the DNS authority for your website, and
- next, to the ISP's DNS to discover the IP (Internet Protocol) address for the domain name used by your website, and then
- to your website!
What is DNS Propogation?
Each and every ISP caches its DNS Records in order to speed up the above process.
In other words, they make a copy of the master records and refer to these locally.
This is quicker than searching for them via the internet every time someone wants view a website.
Unfortunately, each ISP which caches DNS records will only update them periodically and when they do they do so by reference to the ISPs to which they are connected and not from the source.
There is no web standard and so the time gap between periodic updates can vary from a few hours to several days, depending upon the ISP.
This slow updating of the DNS cache by ISPs is what we call Domain Propagation and is why someone may be able to see your website in one part of the world a few hours after it is published, and others may have to wait a few days.
In summmary, it can therefore typically take from anything between 3 and 72 hours for DNS changes to take effect across the entire web.
How to view your website pending propogation?
If required you may view your website at a temporary URL (or web address) whilst waiting for propogation to be completed.
The temporary URL is either:
- accessible via your Hosting Control Panel, or
- the IP address of your hosting account followed by /~hosting-account-username.
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