Erle Robotics Introduction to Networking in Linux


Question 1

Type the command line to make a list of open (listening) ports on your machine.For more clues, you can read 9.1 Secure services and security tips.Nevertheless you don't know, select solution to see the correct answer.

// Introduce on command_line the corresponding bash command line
var Command_line =
var Command_line= netstat -l | grep tcp;
assert(Command_line == netstat -l | grep tcp);
// This is context code available everywhere
// The user will be able to call magicFunc in his code
function magicFunc() {
    return 3;

Question 2

How can you see who connected to your system?:

  • [x] using the comman who
  • [ ] using the command traceroute for following a packet

You can know more about who command in the man page.

Question 3

Using Iptables we want to let the packages just go through this system to be routed. Which command line is the correct one? :

  • [ ] iptables -t filter -P FORWARD ACCEPT
  • [x] iptables -t filter -P FORWARD DROP

Read more in Orders and parameters