Linux Networking Cheat Sheet: Commands Every Developer Should Know

The DevOps & Backend Networking Toolkit

When things break in production, knowing how to debug the network is a superpower. Here are the essential Linux networking commands.

Checking Interfaces and IP Addresses

Forget ifconfig, the modern way is the ip command.

ip addr show       # List all interfaces and IPs
ip link show       # Show link status (up/down)
ip route show      # View the routing table

Finding Open Ports and Listening Services

Use ss (socket statistics) instead of netstat.

ss -tulpn          # Show listening TCP/UDP ports and the process using them
                   # (Requires root/sudo to see process names)

Testing Connectivity and DNS

ping 8.8.8.8       # Test ICMP connectivity
traceroute google.com # Show the path packets take to a host
dig example.com    # Perform a DNS lookup
nc -vz host 80     # Use Netcat to check if a specific port is open

Packet Sniffing

When you need to see exactly what is going over the wire.

tcpdump -i eth0    # Capture all traffic on eth0
tcpdump port 80    # Capture HTTP traffic only
tcpdump src 1.2.3.4 # Capture traffic from a specific IP

Firewall Rules (iptables / ufw)

sudo iptables -L -v -n  # List all current firewall rules
sudo ufw status verbose # If using Uncomplicated Firewall (Ubuntu)