Networking Commands

Networking Commands in Linux

Networking commands help you configure, troubleshoot, and monitor network connections. Below are the most essential commands:

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1. ifconfig (Interface Configuration) – Legacy

Displays and configures network interfaces (deprecated in favor of ip).

Usage:

ifconfig          # Show all active interfaces
ifconfig eth0     # Show details of eth0
ifconfig eth0 up  # Enable eth0
ifconfig eth0 down # Disable eth0

Key Output Fields:

• inet → IPv4 address
• inet6 → IPv6 address
• RX/TX packets → Received/Transmitted data

⚠️ Note: ifconfig is outdated; use ip instead.

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2. ip (Modern Replacement for ifconfig)

The recommended tool for managing network interfaces, routes, and addresses.

Common Subcommands:

Command	Description
ip addr or ip a	Show IP addresses of all interfaces
ip link	List network interfaces (up/down status)
ip route	Display routing table
ip neigh	Show ARP table (MAC ↔ IP mapping)

Examples:

ip addr show eth0    # Show IP of eth0  
ip link set eth0 up  # Enable eth0  
ip route add default via 192.168.1.1  # Set default gateway  

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3. netstat (Network Statistics) – Legacy

Shows network connections, routing tables, and listening ports.

Common Flags:

Flag	Description
-t	TCP connections
-u	UDP connections
-l	Listening ports
-n	Show numerical addresses (no DNS resolution)
-p	Show process using the port

Examples:

netstat -tulnp    # List all listening TCP/UDP ports  
netstat -r        # Show routing table (same as `route -n`)  

⚠️ Note: ss (Socket Statistics) is the modern replacement.

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4. ping (Test Network Connectivity)

Checks if a remote host is reachable using ICMP packets.

Usage:

ping google.com       # Continuous ping (Ctrl+C to stop)  
ping -c 4 google.com  # Send 4 packets and stop  

Key Output:

• time= → Round-trip time (latency)
• TTL= → Time To Live (prevents infinite loops)

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5. traceroute (Trace Network Path to a Host)

Shows the route (hops) taken by packets to reach a destination.

Usage:

traceroute google.com  

Key Output:

• Each line represents a hop (router/gateway).
• * * * means a hop didn’t respond (firewall blocking ICMP).

📌 Alternative:

tracepath google.com  # Works without root privileges  

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Comparison Table

Command	Purpose	Replacement (Modern)
ifconfig	Show/set interfaces	ip addr, ip link
netstat	Show connections/ports	ss
route	Show routing table	ip route
arp	Show ARP cache	ip neigh

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