Networking
DNS, load balancers and proxies, and how to debug a request that never arrives.
About Networking
This is networking from the operator's side: how DNS resolves names, how load balancers and reverse proxies like Nginx spread traffic, how TLS certificates work, and how firewalls decide what gets through.
It ends with a practical skill: debugging a request that never arrives.
Why it matters for placements
When a service is unreachable, DevOps engineers are the ones who find out why. Interviewers ask about DNS records, load balancing, proxies and troubleshooting commands.
What you'll learn
4 topics · 11 lessons, each with practice
- Explain DNS resolution and the common record types
- Configure Nginx as a reverse proxy and load balancer
- Explain TLS certificates and HTTPS termination
- Use tools like curl, dig, ss and traceroute to debug connectivity
Foundation Foundation
Take Foundation testRequired. Enough to clear online assessments and service-company interviews.
Network Essentials
Not startedMost "the site is down" tickets turn out to be a DNS record, a blocked port or a wrong bind address. This topic gives you the working knowledge of DNS, ports and TCP/IP needed to read firewall rules and error messages. It is the base the rest of the networking topics build on.
Interview Ready Interview Ready
Take Interview Ready testRecommended. Enough for technical rounds at good product companies.
Load Balancing & Proxies
Not startedOne server cannot take all the traffic, and users should not notice when one backend dies. Load balancers and reverse proxies spread requests, handle TLS and route by path or host. Configuring and debugging them, especially 502 and 504 errors, is everyday DevOps work.
Network Troubleshooting
Not startedWhen a request never arrives, guessing wastes hours. A few command-line tools let you check each step in order: does the name resolve, is the host reachable, is the port open, what does the service answer. Interviewers love to ask how you would debug "the site is not loading" step by step.
Advanced Advanced
Take Advanced testOptional. For top product companies. Never counted against your readiness.
Service Networking
Not startedAs traffic grows and users spread across the world, and as one app splits into many services, plain load balancers stop being enough. CDNs bring content closer to users, and a service mesh handles security and retries between services. These come up in senior and system design style DevOps interviews.