Linux Learning Journey – Day 7: SSH Practice, Firewall, IP Awareness & Troubleshooting 🐧🔧

Source: Dev.to

What I Practiced Today

Network Connectivity Verification

Before using SSH, I verified that my Ubuntu machine was reachable on the network.

ping 10.255.125.231

If the network is unreachable, SSH will not work.

Verifying Remote SSH Session (ls & pwd)

After connecting via SSH, I checked my current directory and listed files.

pwd
ls

These commands confirmed that:

• I was logged into my Ubuntu system
• I had access to my home directory
• The SSH session was active and stable

Firewall Configuration for SSH (UFW)

To ensure SSH access was not blocked by the firewall, I allowed and verified SSH rules.

sudo ufw allow ssh
sudo ufw status

This confirmed that:

• Port 22 was allowed
• Firewall rules were correctly applied

Checking System IP Address

Since IP addresses can change, I identified the system IP using:

ip a
hostname -I

IP awareness is critical when accessing systems remotely.

Restarting SSH Service

To simulate real‑world troubleshooting, I restarted the SSH service and verified its status.

sudo systemctl restart ssh
sudo systemctl status ssh

Restarting services is a common administrative task.

Reconnecting from Windows via SSH

Finally, I reconnected to my Ubuntu machine from the Windows Command Prompt.

ssh avinash@10.255.125.231

Successful login confirmed that:

• SSH service was running
• Firewall rules were correct
• Network connectivity was stable

Day 7 Takeaway

Consistency wins!