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.

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

Were you frustrated? IP addresses change all the time, so why do we not have to type in a different web address (www.google.com) 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

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

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?

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: 205.181.112.101

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?

DNS continued Domain Name Systems

Review DNS – Domain Name System: the service which translates a URL to an IP URL  Uniform Resources Locator [website address] IP  Internet Protocol [ex: 10.42.132.144 the address of where the device lives on the internet] Each device [computer] requests the IP of the website from the DNS system.

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.

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

Video Code.org – DNS (Begin at 4:12)

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

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?