Networking for DevOps
Follow this page to learn Networking for DevOps, including critical concepts like TCP/IP, DNS, subnetting, firewalls, load balancing, and network protocols essential for managing infrastructure and optimizing connectivity.
This content is specifically structured to help in practical skills with network troubleshooting tools (ping, traceroute, tcpdump) and network automation scripting, helping you crack DevOps interviews.
Important Networking Concepts for DevOps (Interview-Focused)
Networking Fundamentals
✦ Understand how networks work : basics of the Internet, LAN, WAN
✦ OSI model layers, focusing on Layer 3 (Network), Layer 4 (Transport), and Layer 7 (Application)
✦ Core protocols : TCP/IP, UDP, ICMP, HTTP/HTTPS
✦ IP addressing : IPv4, IPv6, public vs. private IPs
✦ Subnetting, CIDR notation, and IP range calculations
✦ Important Ports and their role in network communication like 22 (SSH), 25 (SMTP), 53 (DNS), 3389 (RDP) and others
HTTP, HTTPS & Status Codes
✦ Understand how HTTP and HTTPS work, including request/response structure
✦ Learn the most common HTTP methods : GET, POST, PUT, DELETE, PATCH
✦ Master HTTP status codes :
- 1xx: Informational (e.g., 100 Continue)
- 2xx: Success (e.g., 200 OK, 201 Created)
- 3xx: Redirection (e.g., 301 Moved Permanently, 302 Found)
- 4xx: Client Errors (e.g., 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found)
- 5xx: Server Errors (e.g., 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable)
✦ Know how to interpret and troubleshoot based on status codes in real scenarios
Routing & Switching Basics
✦ Routing basics: static vs. dynamic routing, default gateways, routing tables
✦ Egress and Ingress traffic understanding
DNS & DHCP
✦ DNS : how it resolves domain names, record types (A, AAAA, CNAME, MX, TXT), DNSSEC
✦ DHCP: dynamic IP allocation, configuration, troubleshooting
Network Security
✦ Firewalls (iptables, ufw, firewalld)
✦ VPNs, proxies (forward/reverse), load balancers like Nginx
✦ TLS/SSL for secure communication
✦ Sudo, privilege escalation, network auditing, intrusion detection basics
Web Servers & Load Balancing
✦ Web servers : Nginx, Apache
✦ Reverse proxy concepts, load balancing algorithms (round robin, least connections)
✦ Caching, SSL termination, health checks
Cloud Networking as AWS
✦ VPCs, subnets, routing in AWS/Azure/GCP
✦ Security groups, NACLs, firewall rules
✦ NAT, cloud load balancing, DNS services
Network Troubleshooting & Monitoring
✦ Tools : ping, traceroute, netstat, ss, tcpdump, wireshark, nmap
✦ Analyzing network traffic, diagnosing connectivity issues
✦ Monitoring metrics, setting up alerts for network health
Automation
✦ Scripting for network automation (bash, Python)
✦ Integrate network automation into CI/CD pipelines
Container & Kubernetes Networking
✦ Container networking : namespaces, veth, bridges
✦ Docker network drivers : bridge, host, overlay
✦ Kubernetes networking: CNI plugins, service discovery, ingress controllers
✦ Network policies, service mesh basics
Networking for DevOps in 2025
Mastering Networking for DevOps is essential for every engineer to build robust, scalable, and secure modern infrastructures.
Why Networking Matters in DevOps
Networking for DevOps enables seamless communication between systems, applications, and cloud resources. As cloud deployments, microservices, and containerization increased, deep networking knowledge becomes a important for automating infrastructure, enhancing security, and troubleshooting complex environments.
DevOps Networking Basics
What Is DevOps Networking ?
- The practice of designing, configuring, and managing communication pathways in DevOps pipelines.
- Ensures reliable, secure, and high-speed interaction between application components, databases, CI/CD tools, and end-users.
Why Is It Essential?
- Automates deployments, monitoring, and scaling.
- Prevents bottlenecks and security breaches.
- Key to solving real-world DevOps interview questions and excelling in day-to-day operations.
OSI Model DevOps : Layers Explained
Understanding the OSI model (Open Systems Interconnection) streamlines troubleshooting and design :
| Layer (Top to Bottom) | Function | DevOps Relevance |
|---|---|---|
| Application (7) | User-facing app protocols (HTTP, DNS) | Troubleshooting client-server interactions |
| Presentation (6) | Data translation/encryption (SSL/TLS) | Secure API and web transactions |
| Session (5) | Manages sessions/connection states | Sync and maintain long-running app sessions |
| Transport (4) | Reliable delivery (TCP/UDP) | Controls traffic for APIs, DB, microservices |
| Network (3) | Routing (IP, ICMP) | Routing/forwarding packets across networks |
| Data Link (2) | Physical addressing (Ethernet/MAC) | VLANs, switches, bridging |
| Physical (1) | Hardware, wires, wireless | Infra-level, data cabling, NICs |
OSI Model Layers Explained
- Application Layer: Protocols like HTTP, HTTPS, DNS.
- Transport Layer: TCP/IP vs UDP—reliability vs speed (streaming, video calls).
- Network Layer: IP addressing, routing decisions, ICMP protocol use cases.
TCP/IP, UDP, and Ports in DevOps
What is TCP/IP?
- TCP/IP (Transmission Control Protocol/Internet Protocol) is the foundational suite that governs data exchange across virtually all modern networks, including the internet.
- It breaks large communications into smaller packets, routes them, and reassembles them at the destination.
- TCP and UDP are transport layer protocols within this suite, responsible for how data is sent between applications.
TCP (Transmission Control Protocol)
- Connection-oriented: Initiates a handshake to establish a session before transferring data.
- Reliable Delivery: Guarantees ordered, complete, and error-free data arrival.
- Flow & Congestion Control: Prevents network overload or data loss.
- Use Cases: Web browsing (HTTP/S), file transfers (FTP), email (SMTP), database connections—anywhere reliability is critical.
UDP (User Datagram Protocol)
- Connectionless: No session or handshake; starts sending data immediately.
- Unreliable but Fast: No guarantees of delivery or order, minimal error checking.
- Lightweight: Lower overhead, making it much faster than TCP.
- Use Cases: Real-time applications where speed is essential (DNS queries, live video/audio streaming, Voice over IP, online gaming
TCP/IP vs UDP
| Feature | TCP | UDP |
|---|---|---|
| Type | Connection-oriented | Connectionless |
| Uses | Web, database, file transfer | Streaming, DNS, VoIP |
| Features | Reliable, error-checked, ordered | Fast, lightweight, unordered |
- DevOps tools (e.g., SSH, HTTP) mainly use TCP; DNS and some monitoring may leverage UDP.
Important Ports in DevOps
Services | Port | Use Case |
|---|---|---|
| SSH | 22 | Secure server access |
| HTTP/HTTPS | 80/443 | Web traffic |
| DNS | 53 | Name resolution |
| SMTP | 25 | Email transfer |
| MySQL | 3306 | Database connectivity |
| FTP | 20/21 | File transfers |
Port management and firewalls are vital for network security in DevOps.
IP Addressing in DevOps
IP addressing is fundamental in DevOps for connecting and managing resources across dynamic, scalable cloud and on-premises environments. Every device - be it a server, container, or virtual machine receives a unique IP address, allowing seamless communication within and between networks.
IPv4 vs IPv6
- IPv4: Common, easier to learn, 32 bits (e.g., 192.168.0.1)
- IPv6: Modern, scalable, 128 bits (e.g., 2001:0db8:85a3::8a2e:0370:7334)
Subnetting in Cloud Networking
- Subnetting: Divides networks into logical segments, boosting efficiency and security.
- CIDR Notation: Specifies IP ranges (e.g., 192.168.1.0/24); follow a CIDR notation tutorial to calculate ranges and mask lengths.
Cloud platforms: Use subnetting and CIDR to isolate workloads and allocate private/public IPs.
Routing and Switching in DevOps
- Static Routing: Manual paths, rarely used for large-scale DevOps.
- Dynamic Routing: Automated; essential for cloud and hybrid infrastructures.
- Ingress and Egress Traffic: Ingress = incoming, Egress = outgoing data; firewalls and proxies DevOps control these flows.
- Routers: Decide packet paths using routing tables.
- Switches: Direct traffic at data link layer within networks.
- Protocols: OSPF, BGP (often encountered in AWS/Azure VPCs and hybrid networking).
DNS (Domain Name System)
- Resolves hostnames to IP addresses (e.g., www.stepstodevops.com → 172.217.12.206).
- Key record types: A (IPv4), AAAA (IPv6), CNAME, MX, TXT.
- Understanding DNS concepts is essential for DevOps basics and troubleshooting web deployments.
DHCP (Dynamic Host Configuration Protocol)
- Automatically allocates IPs to hosts.
- Simplifies scaling and dynamic environments (Kubernetes, VMs).
Network Security for DevOps
- Firewalls: Tools (iptables, ufw, firewalld) filter traffic by port, IP, or protocol.
- Proxies: Forward/reverse; enable traffic control and SSL termination.
- VPNs: Secure inter-site or remote connections.
- Security Groups & NACLs: Cloud-native firewalls (AWS, Azure) to control subnet or VM access.
- Network Auditing: Regularly review ingress/egress rules, logs, and alerts.
Load Balancer in DevOps
- Distributes incoming connections to multiple backends.
- Algorithms: round robin, least connection, IP hash.
- Popular tools: Nginx, HAProxy, AWS/GCP/Azure native balancers.
NAT and Security Groups in AWS
- NAT: Network Address Translation; connects private subnets to public internet securely.
- Security Groups: Virtual firewalls controlling inbound/outbound traffic—vital for DevOps cloud security.
Container & Kubernetes Networking Basics
- Container Networking: Virtual networks connect containers (namespaces, bridges).
- Docker Network Drivers: Bridge, host, overlay.
- Kubernetes Networking Basics: CNI plugins (Calico, Flannel), service discovery, Ingress controllers.
- Network Policies: Control inter-pod and external access.
- Service Mesh: Layer for managing service-to-service security and observability.
DevOps Network Troubleshooting Tools
| Tool | Use Case |
|---|---|
| ping | Test connectivity and latency |
| traceroute | Track packet route through networks |
| tcpdump | Capture/analyze network packets |
| nmap | Port scanning and service discovery |
| netstat | Display active connections and listening ports |
| ss | Advanced netstat replacement |
| Wireshark | Deep packet inspection (GUI) |
| curl | Send HTTP(S) requests from CLI |