After building a strong foundation with essential networking tools like ping, traceroute, mtr, and netstat, Day 17 of my Linux learning journey focused on more advanced and practical networking diagnostic commands that are widely used in real-world Linux, Cloud, and DevOps environments.
These tools go a step deeper—helping inspect sockets, analyze DNS at a granular level, debug connectivity, and understand how systems interact on a network.
🔹 What I Learned & Practiced
Today, I explored the following Linux networking commands:
- ss
- arp
- dig
- nc (netcat)
- whois
- ifplugstatus
Each of these plays an important role in production-level troubleshooting.
🔹 ss – Socket Statistics (Modern Replacement for netstat)
The ss command is the modern and faster alternative to netstat.
Example:
- ss -tulnp
✔️ What it does:
- Displays active TCP/UDP sockets
- Shows listening ports
- Identifies which process is using a port
Use case:
Quickly diagnose port conflicts and verify whether services are running (e.g., 80, 443, 3306).
🔹 arp – Address Resolution Protocol Table
arp shows the mapping between IP addresses and MAC addresses.
Example:
- arp -a
✔️ Why it matters:
- Helps debug local network communication
- Identifies devices on the same network
- Useful for troubleshooting LAN and ARP-related issues
🔹 dig – Advanced DNS Query Tool
dig provides detailed DNS information and is more powerful than nslookup.
Example:
- dig google.com
✔️ Key learnings:
- Displays DNS records (A, MX, NS, TXT, etc.)
- Helps analyze DNS propagation and response times
- Essential for cloud-based applications and microservices
🔹 nc (Netcat) – Network Debugging Swiss Army Knife
Netcat is one of the most versatile networking tools.
Examples:
- nc google.com 80
- nc -l 8080
✔️ Use cases:
- Test TCP/UDP connectivity
- Check if ports are open
- Create simple client-server connections
- Debug application-level network issues
- Widely used by DevOps and SRE teams.
🔹 whois – Domain Ownership Information
whois retrieves domain registration details.
Example:
- whois google.com
✔️ What it shows:
- Domain registrar
- Registration and expiry dates
- Organization and country info
Use case:
Useful for security analysis, compliance checks, and understanding domain ownership.
🔹 ifplugstatus – Network Cable & Interface Status
This command checks whether a network cable is connected to an interface.
Example:
- ifplugstatus
✔️ Why it’s useful:
- Confirms physical network connectivity
- Helps diagnose “no network” issues on servers
- Useful in data center and on-prem environments
🔹 Why These Commands Matter in Real-World Systems
These tools are critical because:
- Modern Linux systems rely heavily on socket-level networking
- DNS is a core dependency for almost every cloud service
- Network misconfigurations are a leading cause of outages
- Faster diagnosis reduces downtime and incident impact
- DevOps engineers must debug both network and application layers
🚀 Day 17 Takeaway
Day 17 strengthened my understanding of advanced Linux networking diagnostics.
I now have hands-on experience with:
- Inspecting active sockets and services
- Debugging DNS with precision
- Testing ports and services without full applications
- Understanding ARP and local network behavior
- Verifying physical and logical connectivity
Each day, Linux feels less theoretical and more production-focused.
Networking is not just about connectivity—it’s about visibility, reliability, and control.
Consistency continues to be the real superpower 🔑💪
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