The following are DNS interview questions and answers.

1. Which port does DNS clients use to connect to the DNS server.

DNS Clients do not use any specific ports. They use dynamic ports. During the time the DNS client initiates the request, the operating system would assign a random dynamic port number.

2. Which port does DNS Servers use ?

DNS servers use port number 53

3. Give a practical example where DNS is used

When a user access a website, the operating system uses the DNS protocol to convert the URL name into IP address.

4. Can a user access a website if the DNS server IP address is not configured on its TCP/IP adapter, but is configured on the internet router of the network.

No. For a user to access the website, the TCP/IP adapter should have the DNS server configured.

5. Is the DNS protocol involved when a user pings a website

Yes. For the ping to get a response, the URL has to be resolved into an IP address using the DNS protocol, after which the ping is issued to the resolved IP address.

6. Is the DNS protocol involved when a user pings a public IP address

No. DNS protocol is used for name resolution.

7. Can DNS server IP address be provided as part of DHCP ?

Yes. it can be provided using DHCP.

8. Should the DNS server and default gateway be the same system for a network.

It can either be the same or different systems. There is no mandatory requirement that it should be the same.