The Internet (Computer Networking)

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Osborn King
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1 The Internet (Computer Networking)

2 In what ways do we use the Internet for?

3 Fun facts about the Internet Almost impossible to measure how much data you can access on the Internet Estimated to take about 1,000,000,000 people s brain to store all the data on the Internet.

4 What is the Internet?

5 What is the Internet? consists of collection of computers and related devices (such as: smartphones, tablets, etc) These communicate with each other through wired and wireless technologies to allow us to share information

6 What is the Internet? each of these are routers Another Machine Your Laptop The Internet

7 How does it work? How does it allow us to send or share information? How do machines communicate with another machine? Similar to calling a friend using the phone with the contacts saved

8 This is true in networking also com you internet domain name name of a website (ex: google.com) IP address (Internet Protocol address) Each machine has an IP address

9 What about return address?

10 What about return address? - Your own machine s IP address

11 IP exercises Using the command: ifconfig The ifconfig command is often used to view or modify a computer s IP address.

12 Your machine s IP address is very important because it is used for receiving information so the other machine knows where to send back data.

13 Hands-on Exercise 1: You will use the ifconfig command to retrieve the IP address of the computer you are using. First, you have to open the Command Prompt: Step 1. Click on Dashboard, and then type Terminal. Next, you type in the command: Step 2. At the command prompt, enter: ifconfig The IP address will be a series of numbers following the pattern xxx.xxx.xxx.xxx (i.e., ). Step 3. What is the IP address of your computer? Step 4. Is it different than from your peers?

14 Example screen:

15 How does your machine figure out an IP address of a given domain name? Your browser extracts the domain name and sends it to DNS (Domain Name System). DNS acts as an address book and translates this to an IP address Your machine tries to contact this IP address Domain name: Web browser Domain Name Server DNS IP address: You Google server IP address

16 Domain name to IP address exercise Lesson 1.2 Using the command: nslookup nslookup - lets you look up an IP address given a domain name like com

17 Hands-on Exercise: You are going to use nslookup to lookup the IP address of a website of your choice. Step 1. At the command prompt, type: nslookup website again replacing website with the website you chose (e.g, nslookup google.com). Step 2. How many IP addresses did you find for your website? Step 3. Now copy one of the IP addresses and paste it to your browser and hit enter. What did you get? Step 4. Is it same as typing the domain name( the website name) and hitting enter? Step 5. Even though the results are same, what is the difference?

18 Example screen:

19 Router -- You will need a fastest path for two machines to communicate. -- A device called router is used for this. each of these are routers Another Machine Your Laptop The Internet

20 The routers decide how to get your message across the Internet. And then it forwards your message with the given destination

21 The routers decide how to get your message across the Internet. What would be an efficient path here? 1 -> 2 -> facebook.com you 7 internet 6

22 Traceroute exercises Lesson 1.3 tracepath - lets you see the routers that forward your message to a given destination

23 Hands-on Exercise: We will find how many routers it takes to transfer information from your computer to a website of your choice. Step 1. Go to website Then replacing website with the domain name of the website you chose (e.g, tracepath google.com). Step 2. How many routers forward messages sent from your computer to the website you chose? Step 3. Do you think you would see the same number of routers if you tried this at home?

24 Computer Security

25 Good security standards follow 90/10 rule - 10% of security safeguards are technical - 90% of security safeguards rely on the computer user - YOU How??

26 Types of Security Threats: 1. Social Engineering - an attacker uses human interaction (social skills) to obtain or compromise information about you Examples - Security question - Type of password

2. Phishing Attack legitimate-looking email/webpage in an attempt to gather personal and

27 2. Phishing Attack legitimate-looking /webpage in an attempt to gather personal and financial information from recipients - SF Giants! com/watch? v=gtapmz_ybus

29 Legitimate or not??

30 Legitimate or not??

31 How to protect yourself when on a public computer? - Don t save your login information or enter sensitive information into a public computer - Don't leave the computer unattended with sensitive information on the screen - Erase your tracks, clear cookies - com/watch?v=zp7ebyqbn_m

32 Safety Tips - Have different passwords for all your different accounts - Never have your name or a common word in your password - Never share your password with anyone - Always have alpha-numeric as well as a few special characters in your password Common passwords - com/2014/01/22/most-common-passwords2013_n_ html

33 1. Be aware of suspicious phone calls, text messages, or messages from individuals asking about your information. 2. Do not provide personal/financial information unless you are certain of a person's authority to have the information. 3. Don't send sensitive information over the Internet before checking a website's security

34 5. Pay attention to the URL of a website. Malicious websites may look identical to a legitimate site, but the URL may use a variation in spelling or a different domain (e.g.,.com vs..net). 6. If you are unsure whether an request is legitimate, do not click on it. 7. Install and maintain anti-virus software, firewalls, and filters to reduce some of this traffic

Computer Networking. First, you will use the ifconfig command to retrieve the IP address of the computer you are using:

Computer Networking. First, you will use the ifconfig command to retrieve the IP address of the computer you are using: Computer Networking Computer Networking... 0 Lesson 0. Addressing... 1 Lesson 1. HTML/HTTP... 2 Lesson 2. SMTP... 3 Lesson 3. HTML... 4 Lesson 0. Addressing First, you will use the ifconfig command to