Linux has a tool called iptables, which is essentially a firewall. It has a nice front end program called ufw. In this task, the objective is to use ufw to set up some firewall policies, and observe the behaviors of your system after the policies become effective. You need to set up at least two VMs, one called Machine A, and other called Machine B. You run the firewall on your Machine A. Basically, we use ufw as a personal firewall. Optionally, if you have more VMs, you can set up a firewall at your router, so it can protect a network, instead of just one single computer. After you set up the two VMs, you should perform the following tasks: • Prevent A from doing telnet to Machine B.
• Prevent B from doing telnet to Machine A. Before starting the task, go to the default policy file /etc/default/ufw. find the following entry, and change the rule from DROP to ACCEPT; otherwise, all the incoming traffic will be dropped by default. # Set the default input policy to ACCEPT, DROP, or REJECT. Please note that if # you change this you will most likely want to adjust your rules. DEFAULT_INPUT

Wireless communications is likely to be viewed as an essential part of an enterprise network infrastructure when: select one: a. mobile communication is needed b. communication facilities must be installed at low initial cost c. communication must take place in a hostile or difficult terrain that makes wired communication difficult or impossible d. the same information must be broadcast to many locations

1. the program must provide following functions to extract some statistics. note that the data_list parameter specified in these functions may be the same for all functions or different for different functions—that is your choice. a skeleton file is provided on mirmir. a) open_file()prompts the user to enter a year number for the data file. the program will check whether the year is between 1990 and 2015 (both inclusive). if year number is valid, the program will try to open data file with file name ‘year.txt’, where is the year. appropriate error message should be shown if the data file cannot be opened or if the year number is invalid. this function will loop until it receives proper input and successfully opens the file. it returns a file pointer and year. i. hint: use string concatenation to construct the file name b) read_file(fp)has one parameter, a file pointer read. this function returns a list of your choosing containing data you need for other parts of this project. c) find_average(data_list) takes a list of data (of some organization of your choosing) and returns the average salary. the function does not print anything. hints: i. this is not the average of the last column of data. it is not mathematically valid to find an average by finding the average of averages—for example, in this case there are many more in the lowest category than in the highest category. ii. how many wage earners are considered in finding the average (denominator)

Based on your knowledge of a good network, describe what you think is a perfect network would be. what kind of information and resources could users share on this network. what would the network administrator do? what kind of communication would be used?