Lecture 5- url-dns
- 1. Internet Technology Saman M. Almufti Lecture 5
- 3. • The domain name system (DNS) is a Server represents a large database used for transforming alphanumeric domain names into numeric IP addresses. A decentralized process, name resolution generally takes place on DNS servers’ networks distributed throughout the world. Every internet address you enter into your web browser’s search bar is then forwarded by your router to a DNS server. This server then dissolves the domain name into a numeric sequence and returns a corresponding IP address. • DNS is used in TCP/IP Application layer
- 4. In order to understand the process behind the DNS resolution, it’s important to learn about the different hardware components a DNS query must pass between. For the web browser, the DNS lookup occurs “ behind the scenes” and requires no interaction from the user’s computer apart from the initial request. Web Browser
- 5. Root .com .net.org.edu Nawroz.edu Google.com Yahoo.com Recursor / Resolver • Computer’s DNS cache: If the DNS records are found in your computer’s DNS cache, then the rest of the DNS lookup is skipped and you will be taken directly the requested website • Resolving nameserver: Typically this is your Internet services provider’s (ISP) server • Root Server: The authoritative name servers that serve the DNS root zone, commonly known as the “root servers”, are a network of hundreds of servers in many countries around the world. They are configured in the DNS root zone as 13 named authorities • Top Level Domain (TLD):TLD refers to the last part of a domain name. The most common TLDs include .com, .net, org, and .info. Country code TLDs represent specific geographic locations. For example: .iq represents Iraq. • Alternative Nameserver: This is the part of a domain name which comes right before the TLD Computer Browser
- 6. IP Address
- 8. http://journal.qubahan.com/index.php/qaj URL What’s in a name (URLs) URL = Uniform Resource Locator Contains three parts: Protocol (http, ftp, etc.) Server name (Domain Name) File name, including path Protocol for reading Server name – extension tells type of server File name and path* DomainSub Domain extension a website URL is the location of a specific website, page, or file on the Internet.
- 9. IP Address