What is DNS?


What is DNS?
What does DNS propagation mean?
How long does DNS propagation take?
Why does DNS take so long to propagate?
Can DNS propagation be faster?

What is DNS? top

DNS means Domain Naming System. It is the system that allows a domain name such as www.Maknet.com to be converted into an IP address such as Remembering the name is much easier than remembering the IP address where the website is located.

DNS is a network of name servers around the World that keep track of the IP address of each domain name.

What does DNS propagation mean? top

A server can not hold ALL of the IP information for all of the domain names in the World. Instead, a single server saves some of the information, also called caching. When a request is made for the IP address of a domain name, the server will retrieve the "authoritative" information. It does this by asking a nearby server if it is the authoratative source. It conintues to ask (propagating from server to server) until it gets the authoratiative answer. The next time someone asks for the same information, the server already knows the address (it has been cached) so it sends the saved information to save time. The server will usually update the authoritative information once a day.

Whenever there is a new change to the DNS information, you must wait for the information to "propagate" to the other servers on the Internet.

How long does DNS propagation take? top

Typically, DNS propagation will take from 24 to 48 hours. It can be quicker with some advanced planning and programming, but isn’t guaranteed.

Why does DNS take so long to propagate? top

Almost every server on the internet potentially needs to know the new information. However, by default, the servers will only check once a day. It takes a while before the new message of the new DNS information gets passed down through the servers.

Can DNS propagation be faster? top

With planning, it may potentially be faster. There is a setting in each DNS entry called TTL which stands for Time-To-Live. By default, if it is set to 1 day, it will take one day before the server needs to renew the information. However, if it is set lower, to something like 1 hour, then propagation will speed up considerably.

Unfortunately, the TTL setting is part of the standard but DNS servers are not forced to adhere to the standard. This means that some local ISPs that want to reduce the load on their servers might ignore the setting and only refresh every day or every 3 days!

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