Why Networking Matters

Everything in infrastructure depends on networking. Your servers, databases, APIs, monitoring - they all need to talk to each other. When networking breaks, everything breaks.

The OSI Model (And Why You Should Care)

Yes, everyone learns the OSI model. No, most people don’t use all 7 layers daily. But understanding it helps you troubleshoot faster:

• Physical (Layer 1) - Is the cable plugged in?
• Data Link (Layer 2) - MAC addresses, switches, VLANs
• Network (Layer 3) - IP addresses, routing, subnets
• Transport (Layer 4) - TCP/UDP, ports, connections
• Application (Layer 7) - HTTP, SSH, DNS, etc.

When something’s broken, start at Layer 1 and work your way up. You’d be surprised how often it’s the cable.

Common Issues & How to Fix Them

Can’t Ping?

1. Check if the interface is up: ip link
2. Check if you have an IP: ip addr
3. Check routing: ip route
4. Check firewall: iptables -L or ufw status
5. Check if remote host is up: ping 8.8.8.8
6. Check DNS: dig google.com

Slow Network?

• Check bandwidth: iperf3
• Check packet loss: mtr google.com
• Check interface errors: ethtool -S eth0
• Check CPU/memory on network devices

Essential Tools

• ping - Basic connectivity test
• traceroute - Path discovery
• tcpdump - Packet capture
• netstat / ss - Connection status
• nmap - Port scanning
• wireshark - Deep packet inspection

Next Steps

This is just scratching the surface. Future posts will dive deeper into VLANs, routing protocols, network security, and more.

Stay tuned! 🌐