Welcome to Bucaro TecHelp!

Bucaro TecHelp
HTTPS Encryption not required because no account numbers or
personal information is ever requested or accepted by this site

About Bucaro TecHelp About BTH User Agreement User Agreement Privacy Policy Privacy Site Map Site Map Contact Bucaro TecHelp Contact RSS News Feeds News Feeds

Networking Basics - What is DNS?

Have you ever wondered what happens when you enter, or click on, a web address in your browser? How does your computer connect to the Web site you requested? Part of what makes that happen is the Internet's Domain Name Service (DNS).

Similar to how every telephone has a unique number, every Web site, or "domain" on the Internet has a unique Internet Protocol (IP) address. IP addresses are 32 bit numbers represented by four bytes separated by dots. Each byte can represent a number from 0 to 255, therefore the highest IP address

People have difficulty remembering 12 digit numbers, so web sites are are identified by names like www.sitename.com instead of their IP address. DNS is a database of domain names and their corresponding IP addresses.

In the beginning, every computer on the Internet had a list of all the domain names and their corresponding IP addresses. But that quickly became unwieldy. Now the domain name database and domain name to IP address translation is performed by computers assigned as DNS servers.

Each DNS server has data only about the domains it is serving. When a computer makes a request to its DNS, it is possible that the DNS server doesn't have the data required to answer the request. Special "root name" servers hold a list of DNS servers for top-level domains, like .com, .org, .edu etc. For example, the top-level DNS for .com lists the DNS servers for domain names ending in ".com".

If a DNS server doesn't have the data to answer a request, it makes a request to a root-name server. The root-name server will return the address of a DNS server where the data can be found.

Each domain name on the Internet is required to be listed on a minimum of two DNS servers. This is so if one of the DNS servers goes down, requests for the domains address can still be answered.

DNS also performs IP address to domain name translation. This makes it possible for servers to log accesses and for administrators to perform certain administrative and security tasks.

Information communicated over the Internet is broken into "packets" by Transmission Control Protocol (TCP). TCP attaches the IP address of the requested domain to each packet so that they can be routed to the domain. TCP also attaches the IP address of the requesting computer to the packets so that responses can be routed back.

When you enter, or click on, a web address in your browser, the Internet's Domain Name Service (DNS) translates the web address to the web sites IP address. This is only part of the story of how your computer connects to the Web site you requested. In a future article you'll learn about the amazing process performed by routers.

More Networking Basics:
• Servers - Racks, Blades and Towers
• Virtualization For Dummies Cheat Sheet
• Workgroups and Domains
• The Function of the Three Planes of Junos Network OS
• Network Administrator Street Smarts: A Real World Guide to CompTIA Network+ Skills
• What is Cloud Computing?
• Best CompTIA Network+ Certification Exam Preparation Materials
• Computer Number Systems Made Simple
• Definition: Cloud Computing
• How to Study For and Pass the CompTIA Network+ Exam

RSS Feed RSS Feed

Follow Stephen Bucaro Follow @Stephen Bucaro

Computer Networking Sections

Fire HD
[Site User Agreement] [Privacy Policy] [Site map] [Search This Site] [Contact Form]
Copyright©2001-2021 Bucaro TecHelp 13771 N Fountain Hills Blvd Suite 114-248 Fountain Hills, AZ 85268