Networking

How to use SSH tunnels to securely access remote services, expose local servers, set up SOCKS proxies, and hop through bastion hosts.

A methodical approach to diagnosing network problems on Linux — working layer by layer from physical connectivity to application-level issues.

How to control incoming and outgoing network traffic on a Linux host using iptables and nftables — rules, chains, policies, and practical configurations.

The essential commands for checking your IP address, gateway, DNS, and connectivity — plus how to configure network settings on a Linux host.

A practical guide to DNS covering record types, resolution flow, caching, and common tools for troubleshooting.

Deeper networking concepts mapped to OSI layers — packet captures, TCP internals, MTU issues, NAT, firewalls, and L4 vs L7 load balancing.

A practical breakdown of the 7 OSI layers, what happens at each one, the protocols involved, and how to troubleshoot at each level.

Production-level networking — BGP, anycast, container networking, mTLS, eBPF, service meshes, and network observability.