Linux Series Day 8: Linux Networking Basics – Understand ip, ping, netstat & More

Networking is the heart of Linux systems, especially for DevOps Engineers. Whether you're connecting to a server, debugging a network issue, or configuring an IP address — Linux gives you powerful tools.

In this article, we’ll explore some basic Linux networking commands that every beginner must know!

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🌐 1. Check Your IP Address — ip a

Instead of the old ifconfig (now deprecated), use the ip command:

ip a

🧠 What it shows:

All available network interfaces

Assigned IP addresses

Loopback interface (lo)

Ethernet or Wi-Fi adapter info

\> Bonus: To only see your IPv4 address:

ip -4 a

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📶 2. Test Connectivity — ping

ping is the easiest way to check if your system can reach another IP or website.

ping google.com

🧠 What it shows:

Whether the host is reachable

Round-trip time (latency)

Packet loss

\> Stop the ping loop: Press Ctrl + C

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🌍 3. View Network Routes — ip route

To see the routing table (how your machine decides where to send packets):

ip route

🧠 Use case: Helps you identify the default gateway, and which interface is used for which IP.

Example output:

default via 192.168.0.1 dev wlan0

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📡 4. Active Network Connections — netstat or ss

🔹 netstat shows current network connections:

netstat -tuln

-t = TCP

-u = UDP

-l = Listening ports

-n = Show numbers (no domain names)

🔹 ss is the modern and faster alternative to netstat:

ss -tuln

🧠 Use case: See which services are running and on which ports.

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🔧 5. DNS Lookup — dig & nslookup

When you want to resolve domain names to IP addresses:

dig google.com

or

nslookup google.com

🧠 Use case: Helpful when you think there’s a DNS issue or you're configuring a custom DNS.

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🌐 6. Download from Web — curl or wget

Want to download something from a URL?

curl https://example.com

or

wget https://example.com/file.txt

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🧪 Bonus: Monitor Traffic with tcpdump

To sniff real-time packets (requires sudo):

sudo tcpdump -i any

🧠 Use this for debugging and deep inspection, but be careful—can get overwhelming!

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🎯 Summary Table

Command Purpose

ip a Show IP address info

ping Test connectivity

ip route View routing table

netstat/ss Show active network connections

dig / nslookup DNS lookups

curl / wget Download via terminal

tcpdump Packet monitoring/sniffing

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🧠 Final Thoughts

As a future DevOps engineer 💻, these Linux networking tools are your eyes into the system’s communication. Whether debugging, deploying, or configuring—these commands will save your day!

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🔜 Coming Up Next: Day 9 — [Let me know your next topic!]

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