IP Addresses and the Domain Name System
IP addresses identify network interfaces for packet delivery. DNS resolves domain names to resource records, including IP addresses.
Summary
IP addresses identify network interfaces for packet delivery. DNS resolves domain names to resource records, including IP addresses. Name resolution and IP routing are separate operations: successfully resolving a name does not establish that its destination is reachable.
| Address format | Size | Usual representation |
|---|---|---|
| IPv4 | bits | Four decimal octets separated by dots |
| IPv6 | bits | Colon-separated hexadecimal groups |
CIDR specifies network-prefix length. In , the first bits identify the network prefix. Prefixes allow routers to represent whole networks rather than individual destinations. Private IPv4 addresses are not globally routed on the public Internet. NAT translates between address spaces, commonly allowing private networks to share a public address.
🧠 Key Concepts
- Network Interfaces
- CIDR Prefixes
- Private IPv4 Addresses
- Network Address Translation
- DNS Hierarchy
- Recursive Resolution
- DNS Resource Records
- Time to Live
- DNS Caching
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In the CIDR address , what does the suffix specify?
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IP Addresses and the Domain Name System
📘 Overview IP addresses identify network interfaces for packet delivery, while the Domain Name System (DNS) resolves domain names to resource records, including IP addresses. Address prefixes support routing, and DNS uses a distributed hierarchy with caching to resolve names efficiently.
🧠 Key Idea IP addressing determines where packets can be delivered; DNS lets applications discover addresses through names. DNS resolution and IP routing are separate operations.
⚔️ Core Details: - CIDR notation specifies the network-prefix length: in , the first bits form the network prefix. - Private IPv4 addresses are not globally routed on the public Internet. - Network Address Translation (NAT) translates addresses between address spaces, commonly allowing private IPv4 networks to share a public address. - The DNS hierarchy delegates authority from the root to top-level domains and onward to authoritative servers for delegated zones. - A recursive resolver follows referrals from DNS servers to obtain an answer on a client's behalf. - Cached DNS records remain reusable until their time to live (TTL) expires.
🎯 Why It Matters: - DNS allows a service's address to change without requiring users to learn a new domain name. - Separating name resolution from connectivity helps distinguish DNS failures from routing or reachability problems. - Address prefixes let routers represent whole networks rather than maintain a separate route for every destination. - Caching reduces lookup latency and DNS traffic but can delay the visibility of record changes.
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Part of 🗄️ BS Information Systems — 1st Year
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