Domain Name System (DNS)
Security+ 🏆 • Protocols 🔗 • Network Security 🌐
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Difficulty: free
Definition
DNS is the system that translates domain names into IP addresses and other records computers use to locate services. It is a distributed, hierarchical database that supports web browsing, email delivery, and many other network functions.
Examples
- A browser looks up www.example.com and receives an IP address so it can connect to the website.
- An email server queries MX records to learn which mail servers accept messages for a domain.
Discover 🔎
DNS is often described as the phonebook of the internet, but it is more like a directory service for networks. It maps names to many kinds of answers, such as IP addresses, mail routing, and service locations. Because most connections begin with a DNS lookup, DNS reliability and DNS security strongly influence whether services are reachable and whether users end up at the right destination.
Remember: If DNS is slow or wrong, many applications look broken even when the servers are healthy.
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