Networking for DevOps – Practical & Interview-Focused Guide

Why Networking is Important for DevOps?

DevOps engineers manage:

• Cloud infrastructure
• Containers & Kubernetes
• CI/CD pipelines
• Monitoring & security

All of these depend on networking.

🧱 Core Networking Concepts (Must-Know)

🔹 IP Addressing

• IPv4 / IPv6
• CIDR (/24, /16)
• Private IPs:
• 10.0.0.0/8
• 172.16.0.0/12
• 192.168.0.0/16

🔹 Subnetting

• Divide networks for:
• Security
• Performance
• Example:

VPC: 10.0.0.0/16

Subnet: 10.0.1.0/24

🔹 DNS (Very Important)

• Converts name → IP
• Used in:
• Kubernetes services
• Load balancers
• Microservices

Tools:

nslookup google.com

dig google.com

☁️ Cloud Networking (AWS / Azure)

AWS Example

• VPC
• Subnets (Public / Private)
• Internet Gateway
• NAT Gateway
• Security Groups
• NACL

Azure Example

• VNet
• Subnets
• NSG
• Load Balancer

🐳 Container Networking

Docker

• Bridge network
• Host network
• Overlay network

Command:

docker network ls

Kubernetes Networking (Interview Favorite)

• Every Pod gets an IP
• No NAT between Pods
• Service provides stable IP

Service types:

• ClusterIP
• NodePort
• LoadBalancer
• Ingress

🔄 Load Balancing

• Distributes traffic
• Types:
• L4 (TCP/UDP)
• L7 (HTTP/HTTPS)

Examples:

• NGINX
• AWS ALB / NLB

🔐 DevOps Networking Security

• Firewalls
• Security Groups / NSG
• Network Policies (K8s)
• Zero Trust
• TLS / HTTPS

🧪 Troubleshooting Tools (Must Know)

ping

traceroute

curl

netstat

ss

tcpdump

🔁 CI/CD & Networking

• GitHub Actions runners
• Jenkins agents
• Webhooks
• Firewall port opening

🎯 Interview One-Line Answers

Q: Why subnetting in cloud?

A: Isolation and security.

Q: What is NAT Gateway?

A: Allows private subnet internet access.

Q: How do pods communicate?

A: Via flat network with Pod IPs.

Q: What is Ingress?

A: HTTP routing into Kubernetes.