- DNS is an internet service that translates domains names into IP address.
- The domain names are in alphabetic, because they are easier to remember than remembering IP address.
- DNS is translates domain name into it's corresponding IP address.
- For example, www.google.com translate to 173.194.36.51
Why DNS is important?
- DNS is like a phone book for the internet. If you know a person's name but don't know their telephone number, you can simply look it up in a book .DNS provides this same service to the internet.
How DNS works?
- If we do not have DNS, then we have to remember all IP addresses. It is impossible.
| Primary DNS | Secondary DNS |
|---|---|
| It is referred as Master Server. | It is referred as Slave Server. |
| It is responsible for reading data related to the domain zone and also responsible for communication with secondary server. | It is responsible for obtaining zone data from the primary DNS server immediately after being set up. |
| It is the read/write copy of the DNS database. | It is the read only copy of the DNS database. |
| We can add new records and make updates in Primary DNS. | We can not add a records it takes directly from Primary DNS. |
| It has only one zone capacity. | It has 255 zones capacity. |
| It works as a main server for all tasks. | It works as a backup server when primary server fails. |
| Primary DNS responds for all domains. | DNS server offers security through redundancy. |
More Examples on DNS working:
Example for Primary DNS vs Secondary DNS:
See below video for more details: