1. Warm up Activity:
As you walk in, take your IP address. DO NOT share it with your classmates.
For the next 5 minutes, your goal is to complete an accurate list of IP addresses and names for all students in the room.
You may only talk to one person at a time, but you may exchange as much information with that person as you want.

2. How the Internet Works: DNS
Domain Name System
How the Internet Works: DNS

3. Were you frustrated?
IP addresses change all the time, so why do we not have to type in a different web address ( every time they change?
Google and other websites IP address will not change that often. Only if they change providers.
Your phone will change IP addresses as you move around – Cell phone  Cellular  connected to ‘cells’ of towers which relay your signal.
How does a computer remember where to go?
How would a mail carrier know where to go if your address changed all the time?
Verizon
Nanticoke Rd.
North Salisbury
Sharptown

4. Activity review:
We created individual lists, which is highly inefficient
The internet has a centralized list, which is much less frustrating 

5. Review: IP addresses, Protocols
A Protocol is a ‘rule’ or agreement. The term comes from diplomacy. Two representatives from countries meeting each other would not want to offend the other, so a shared form of etiquette and format is set ahead of time.
Computers use a similar experience. Computers are guarded, yet willing to communicate with each other based upon set rules (just like a diplomat).
IP stands for Internet Protocol. What do you think are some ‘rules’ or etiquette customs, computers might share?

6. What is a domain name?
Domain – Think “home” (Dominion, Territory, ‘region w/ specific feature’)
When we type a web address:
www. (World Wide Web) “Hey! Take me to the internet!” [unnecessary now]
Salisbury The Domain name – specific to its nature; “home”
.edu The top level domain name (also specific to its nature  think Education)
However a computer can’t really ‘read’ a domain name
(computers work better w/ numbers; we work better w/ words, so we compromise!)
The domain name must be “resolved” (think – two countries agree on a resolution)
Thus the computer changes the web address to a number ex:

8. Let’s find the IP addresses of various sites
Use the worksheet to find the addresses of listed sites.
Also, find the sites of 5 other of your favorite sites
Observations?

9. DNS continued
Domain Name Systems

10. Review
DNS – Domain Name System: the service which translates a URL to an IP
URL  Uniform Resources Locator [website address]
IP  Internet Protocol [ex: the address of where the device lives on the internet]
Each device [computer] requests the IP of the website from the DNS system.

11. DNS - issues
DNS is the large-scale system that translates human-readable web addresses into their numeric IP addresses so that computers can communicate.
This system however was not designed to be secure and that has resulted in some major security incidents over time.

12. Let’s find our IP address
If you have access to the Command Prompt (the C:/ prompt) you can type in CMD in the windows search bar to access it.
In the prompt, type ipconfig and you will see your computer’s IP address
If not: go to pingtool.org
Type in a website  wcboe.org code.org whatever you’d like
Look up country, #of hops to get there and IP address

13. Video
Code.org – DNS (Begin at 4:12)

14. DNS Attacks Research DNS attacks – Online and using Moodle links
Group 1: look up GOVERNMENT DNS attacks
Group 2: look up Attacks on commercial sites (companies)
Group 3: look up Denial of Service attacks

15. What is DNS Why does the Internet use IP addresses?
Why don’t we need to know IP addresses?
Why do we need a Domain Name System?
Why don’t we all maintain our own DNS?
Is there one big DNS for the entire Internet?
How do you think all these DNS servers are maintained?