UNIT 9: Networking Basics
A Linux computer without internet is just a calculator. To control the world, you must connect to the Grid.
1. The New Standard (IP vs Ifconfig)
In the old days, we used ifconfig. Today, that command is dead. We use IP.
To find your own address:
ip a # Shows IP Address (e.g., 192.168.1.5)
2. Reconnaissance (PING)
Before you attack or connect to a server, you must verify it is alive. We use sonar.
ping 8.8.8.8 # Pings Google's DNS server
Press Ctrl+C to stop the ping!
3. Remote Access (SSH)
Secure Shell (SSH) is the most important tool for a Linux Admin. It allows you to log into a computer on the other side of the world and control its terminal.
ssh user@10.10.10.5
4. Troubleshooting (SS)
Is your web server actually running? Who is connected to you?
We use ss (Socket Statistics) to check open ports.
ss -tuln # Shows all listening ports (TCP/UDP)
⚠️ MISSION BRIEFING
There is a target server at IP 10.10.10.99.
- Ping the server to see if it is online.
- SSH into the server as user 'admin'.
root@learnix:~#