SSH connection basics in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to connect to a remote server using SSH.

Linux CLI

ssh [1]@example.com

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

Apassword

Buser

Cconnect

Dremote

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'password' instead of username in the ssh command.

Omitting the username entirely.

The SSH command requires the username before the @ symbol to connect to the remote server.

2fill in blank

medium

Complete the code to specify a custom port when connecting via SSH.

Linux CLI

ssh -p [1] [e-mail]

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

A443

B80

C22

D2222

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 80 or 443 which are for web traffic, not SSH.

Using the default port 22 when a custom port is needed.

The -p option specifies the port number for SSH. Port 2222 is a common alternative SSH port.

3fill in blank

hard

Fix the error in the SSH command to connect to the server.

Linux CLI

ssh [1]example.com -p 22

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

Auser@

B22

Cconnect

D2222

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the '@' between username and hostname.

Placing the port option before the hostname.

The username must be before the @ symbol in the hostname, so the command should be 'ssh [e-mail] -p 22'.

4fill in blank

hard

Fill both blanks to create an SSH command that connects to 'server.com' as 'admin' on port 2200.

Linux CLI

ssh [1]@[2] -p 2200

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

Aadmin

Buser

Cserver.com

Dexample.com

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping username and hostname positions.

Using the wrong hostname.

The username is 'admin' and the hostname is 'server.com' to connect correctly.

5fill in blank

hard

Fill all three blanks to create a command that copies a file 'file.txt' from local to remote server 'host.com' as user 'alice' using SCP.

Linux CLI

scp [1] [2]@[3]:~/

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

Afile.txt

Balice

Chost.com

Ddocument.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong file name.

Swapping username and hostname.

Omitting the colon ':' after hostname.

The SCP command syntax is 'scp localfile user@hostname:destination'. Here, 'file.txt' is copied to '[e-mail]' home directory.

Practice

1. What does the command ssh user@hostname do?

easy

A. Lists files on the remote computer.

B. Copies files from the remote computer to local.

C. Starts a secure connection to the remote computer as 'user'.

D. Deletes the user account on the remote computer.

Solution

1. Step 1: Understand the ssh command purpose

   The ssh command is used to securely connect to another computer over a network.

2. Step 2: Analyze the syntax ssh user@hostname

   This syntax means connect as 'user' to the computer identified by 'hostname'.

3. Final Answer:

   Starts a secure connection to the remote computer as 'user'. -> Option C

4. Quick Check:

   ssh user@hostname = Secure connection [OK]

Hint: ssh user@host means connect securely as user [OK]

Common Mistakes:

• Thinking ssh copies files instead of connecting
• Confusing ssh with file listing commands
• Assuming ssh deletes accounts

2. Which of these is the correct syntax to connect to a remote server with ssh?

easy

A. ssh user@hostname

B. ssh -connect user hostname

C. ssh connect user@hostname

D. ssh user hostname

Solution

1. Step 1: Recall ssh command syntax

   The correct syntax is ssh user@hostname without extra words or flags for basic connection.

2. Step 2: Check each option

   Options A, B, and D have incorrect syntax or missing '@' sign.

3. Final Answer:

   ssh user@hostname -> Option A

4. Quick Check:

   Correct ssh syntax = ssh user@hostname [OK]

Hint: ssh always uses user@hostname format [OK]

Common Mistakes:

• Adding extra words like 'connect' in command
• Omitting '@' between user and hostname
• Using flags incorrectly for basic ssh

3. What will happen if you run ssh alice@192.168.1.10 and the password is correct?

medium

A. You will see a list of files on your local computer.

B. The remote computer will shut down.

C. Your local files will be deleted.

D. You will be logged into the remote computer as user alice.

Solution

1. Step 1: Understand ssh login process

   Running ssh with user and IP tries to connect and log in to that remote machine.

2. Step 2: Check what happens on correct password

   If password is correct, you get a command prompt on the remote machine as that user.

3. Final Answer:

   You will be logged into the remote computer as user alice. -> Option D

4. Quick Check:

   ssh + correct password = remote login [OK]

Hint: Correct password means remote login success [OK]

Common Mistakes:

• Thinking ssh shuts down remote machine
• Confusing ssh with file deletion
• Assuming ssh lists local files

4. You try to connect with ssh [e-mail] but get the error: Permission denied (publickey). What is the likely problem?

medium

A. You typed the wrong hostname.

B. Your SSH key is missing or not accepted by the server.

C. The server is turned off.

D. You forgot to install ssh on your computer.

Solution

1. Step 1: Understand the error message

   "Permission denied (publickey)" means the server expects an SSH key for authentication but did not accept yours.

2. Step 2: Identify cause of error

   This usually means your SSH key is missing, not loaded, or not authorized on the server.

3. Final Answer:

   Your SSH key is missing or not accepted by the server. -> Option B

4. Quick Check:

   Permission denied (publickey) = SSH key issue [OK]

Hint: Permission denied (publickey) means SSH key problem [OK]

Common Mistakes:

• Assuming hostname typo causes this error
• Thinking server power state causes this error
• Believing ssh must be installed locally to connect

5. You want to connect to a remote server at example.com as user admin but the server uses a non-standard port 2222. Which command will connect correctly?

hard

A. ssh -p 2222 [e-mail]

B. ssh [e-mail]:2222

C. ssh [e-mail] -port 2222

D. ssh [e-mail]

Solution

1. Step 1: Recall how to specify a port in ssh

   The correct flag to specify a port is -p followed by the port number.

2. Step 2: Analyze each option

   ssh -p 2222 [e-mail] uses -p 2222 correctly. Options A, C, and D use incorrect syntax or wrong placement.

3. Final Answer:

   ssh -p 2222 [e-mail] -> Option A

4. Quick Check:

   Use -p to specify port in ssh [OK]

Hint: Use ssh -p port user@host for custom ports [OK]

Common Mistakes:

• Putting port after hostname with colon
• Using -port instead of -p
• Changing hostname to include port number