Networking, DNS Basics

This page contains information for everyday computer users about the campus DNS (Domain Name System) service.

What is DNS for?

DNS (which stands for Domain Name System) is the system computers use to locate each other across the Internet.

In simplest terms, DNS is like an enormous phone book for translating human-readable computer names (such as www.example.com) into machine-readable IP address numbers (such as 198.51.100.17 or 2001:db8::17) which your computer can then use to establish a network connection (i.e. place a call) to the other computer.

Domains are collections of computers that belong together. For example, any web page with a domain name ending in .edu belongs to an educational institution. Any web page with a domain name ending in .illinois.edu belongs specifically to the educational institution which is University of Illinois at Urbana-Champaign.

What is a DNS server?

A DNS server is a computer that provides access to this global and constantly-changing phone book. When your computer needs to know the IP address for www.example.com, it asks the DNS server; the DNS server looks up the answer and sends it back to your computer.

Do I need to know about DNS servers?

In most cases, you won't need to know about DNS servers or change your computer's configuration to access them.

Most modern computers can automatically learn about the campus DNS servers through a service known as DHCP. If you're not having any problems with your network connection, you don't need to change anything.

However, in some cases, you might need to override DHCP's automatic DNS detection and configure your computer to use a specific DNS server.

What are the campus DNS servers' IP addresses?

If a network connection's configuration process asks for DNS server information, and choosing the "automatic" or "DHCP" option doesn't work for you, you can reach the campus DNS servers using the following IPv4 address:

130.126.2.131

and/or the following IPv6 address:

2620:0:e00:a::1

Technical note: only recursive DNS servers are used directly by your computer as described above.  Please do NOT configure your computer to use the IP addresses of dns1.illinois.edu, dns2.illinois.edu, or dns3.illinois.edu as its DNS servers. Those are authoritative-only servers which cannot answer queries for external domain names such as google.com, which in general means that a computer attempting to use them as its DNS servers will not be able to successfully navigate the Internet.

What are the benefits of using the campus DNS servers?

Several well-known companies now offer public DNS servers which can be used by anyone, but the campus DNS servers are specifically designed to provide the best possible user experience while your computer is on the University of Illinois campus network.  Benefits of using the campus DNS servers include:

  • optimized experiences for some University of Illinois services which intentionally provide different DNS answers to on-campus vs off-campus clients
  • resolution of certain DNS zones which are intentionally restricted to allow queries from University clients only
  • blocking of known malicious domains by Privacy and Information Security (see Security, Malicious domain blocking)
  • troubleshooting support by Technology Services if you report a problem that appears related to DNS resolution



Keywords:DNS, Domain Name System, DHCP, servers, IP address, automatic, resolver, nameserver   Doc ID:47914
Owner:IPAM I.Group:University of Illinois Technology Services
Created:2015-03-03 10:04 CSTUpdated:2019-10-01 07:30 CST
Sites:University of Illinois Technology Services
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