DNS: domain name to IP address translator

DNS stands for Domain Name System. It works like a phonebook for the internet: when you type a domain like 'example.com', DNS looks up the matching IP address, such as 93.184.216.34. Without DNS, you would need to memorise numbers for every website. The key contrast is that DNS handles name resolution, not data transport. If DNS fails, you cannot reach sites by name, but tools like ping or traceroute to an IP address may still work perfectly.

A common exam trick is presenting a scenario where a user can access a website by its IP address but not by its domain name. This points directly to a DNS problem, not a network or internet outage. Another hint: check if multiple domains fail — that suggests a local DNS issue, whereas a single domain failing might be a problem with that domain's DNS records. Also remember that DNS uses UDP port 53 for queries and TCP port 53 for zone transfers, so if those ports are blocked, resolution fails.

To test your understanding quickly, ask yourself: if you can ping 8.8.8.8 but cannot browse 'google.com', what is broken? The answer is DNS, not your internet connection. A memory aid: DNS = Domain Name Service, not Data Network Service. Keep this distinction clear to avoid mixing up name resolution with connectivity.