Port scanning basics in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to scan port 80 on a target IP using netcat.

Bash Scripting

nc -zv [1] 80

Drag options to blanks, or click blank then click option'

A192.168.1.1

B255.255.255.0

Cgoogle.com

Dlocalhost

Attempts:

3 left

💡 Hint

Common Mistakes

Using a network mask like 255.255.255.0 instead of an IP address.

Using a domain name that might not respond on port 80.

The nc -zv command scans the specified port on the given host. Here, localhost refers to your own machine.

2fill in blank

medium

Complete the code to scan ports 20 to 25 on a target IP using a for loop.

Bash Scripting

for port in [1]; do nc -zv 127.0.0.1 $port; done

Drag options to blanks, or click blank then click option'

A{20..25}

B20-25

C20 21 22 23 24 25

D20,21,22,23,24,25

Attempts:

3 left

💡 Hint

Common Mistakes

Using a dash like '20-25' which is not valid for bash loops.

Using commas which are not recognized as separators in bash loops.

The brace expansion {20..25} generates the sequence of numbers from 20 to 25, which the loop iterates over.

3fill in blank

hard

Fix the error in the code to scan port 443 on a target IP stored in variable $target.

Bash Scripting

nc -zv [1] 443

Drag options to blanks, or click blank then click option'

Atarget

B$target

C${target}

Dtarget$

Attempts:

3 left

💡 Hint

Common Mistakes

Using the variable name without the dollar sign.

Placing the dollar sign after the variable name.

Using ${target} ensures the variable is expanded correctly in bash.

4fill in blank

hard

Fill both blanks to create a loop that scans ports 80 to 82 on IP 10.0.0.1.

Bash Scripting

for port in [1]; do nc -zv [2] $port; done

Drag options to blanks, or click blank then click option'

A{80..82}

B10.0.0.2

C10.0.0.1

D80 81 82

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong IP address.

Using a space-separated list instead of brace expansion for ports.

The brace expansion {80..82} generates ports 80, 81, and 82. The IP 10.0.0.1 is the target to scan.

5fill in blank

hard

Fill all three blanks to create a dictionary-like output of ports and their status using a loop and conditional.

Bash Scripting

for port in [1]; do
  nc -z [2] [3] $port && echo "$port: open" || echo "$port: closed"
done

Drag options to blanks, or click blank then click option'

A{22..24}

B127.0.0.1

C-v

D192.168.0.1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong IP address.

Omitting the verbose flag which helps see connection status.

The loop scans ports 22 to 24 on localhost (127.0.0.1) with verbose flag -v. The conditional prints if the port is open or closed.