Question: Examine VoIP Traffic on the LAN
Today's app marketplace provides a plethora of options for phone calls over the Internet, two of the most popular being Skype (recently acquired by Microsoft) and Google Hangouts. In this project, you explore another program called Viber that is also available for multiple platforms and devices. Viber is primarily a voice calling app, as opposed to video (although video features are being added and improved). Skype, Google Hangouts, and Viber all provide free calls to other users of the same app, so using the same app that your friends do is vital to maximizing the app's usefulness. Although Skype enjoys a large market share in the United States, other apps, such as Viber, are more popular in other countries. For this reason, Viber can be especially useful in providing free phone calls via free Wi-Fi hot spots while traveling outside of the United States. Viber attaches the user account to the user's mobile phone number, so the mobile app must be installed first:
1. On your smartphone (iPhone, Android, Windows Phone, or BlackBerry), find the Viber app in your application store and install it. Complete the registration process.
2. To install the desktop app on your computer (Windows, Mac, or Linux), go to viber.com, click Get Viber, and complete the installation process.
3. Connect with a friend or classmate through Viber so this person is listed in your contacts list.
Next, you use Wireshark to observe the traffic Viber creates on your network. This portion of the project will be easiest if you use a wired connection to somewhat limit the amount of traffic that Wireshark will detect.
4. Close all Web browsers and any other apps you can think of that might be creating Web traffic on your computer, except Viber.
5. Open Wireshark, and then click Capture Options. In the Wireshark: Capture Options window, select the interface to capture (preferably a wired connection instead of a wireless connection).
6. Uncheck Use promiscuous mode on all interfaces so that promiscuous mode is disabled for this capture, and then click Start.
7. Watch the capture for a minute or two and see if you notice any anomalies in the messages being captured. Are there large numbers of a particular type of message?
8. Watch the row numbers and when the capture hits a round number that is easy to remember (like 10,000), make a call to your contact in Viber. After about two rings, or after the person picks up, stop your capture in Wireshark.
9. Examine the capture from the point when you initiated the call. What change in the types of messages do you notice? Do any other anomalies stand out to you?
10. You should see large numbers of messages being exchanged between your computer and a public IP address. Perform an IP address lookup online using a Web site such as who.is or whois.domaintools.com to determine who owns the Web site. Google the name of that company and see if it is connected to the Viber app. You might want to do a search for both the name of the company and Viber's name together in order to determine if there is a connection
11. If the company you found is not connected with Viber, look for another IP address in your capture that appears very frequently and try that one. Keep looking until you find the connection. What is the name of the company you found?
12. Open Task Manager and use the Resource Monitor to determine which port Viber is listening on and which protocol (TCP or UDP) the app is using. What information did you find?