Networking / Servers
IP, DNS, firewalls, Nginx, and SSL configuration
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Networking / Servers guides15
keepalived VRRP: Setting Up Virtual IP Failover with Health Checks and Split-Brain Prevention
Share a virtual IP across nodes with VRRP so traffic fails over without downtime when the master dies. Covers MASTER/BACKUP setup, vrrp_script health checks, and split-brain prevention for production.
BIND9 Authoritative DNS: Setting Up Forward and Reverse Zones, Zone Transfers, and DNSSEC
Set up an authoritative nameserver with BIND9. Covers named.conf layout, forward and reverse zone files, SOA/NS/MX records, master/slave zone transfers, and DNSSEC basics.
Caddy Reverse Proxy: Automatic HTTPS with Let's Encrypt, Caddyfile Setup, and Zero-Downtime Reloads
A practical operations guide covering Caddy's automatic HTTPS (ACME), Caddyfile syntax, reverse proxying, headers, compression, logging, and zero-downtime configuration via the API.
SSH Port Forwarding: Reaching Private Databases with -L, Exposing Internal Services with -R, and SOCKS Proxies with -D
How to reach databases and Redis with local port forwarding, expose an internal server with remote port forwarding, and set up a SOCKS proxy with dynamic port forwarding.
curl · wget Practical Guide — API Testing and File Downloads
How to test REST APIs with curl—including headers, authentication, and request bodies—how to download and mirror files with wget, and when to choose each tool.
WireGuard VPN: Setting Up a Server and Clients, Generating Keys, and Routing Traffic
Covers WireGuard server and client installation, key generation, configuration files, adding peers, and routing so you can set up site-to-site VPN and remote access.
Apache Virtual Host Configuration — Virtual Host and Module Management
Practical Apache setup for per-domain virtual hosts, covering module enablement, redirects, SSL integration, and separate logs.
iptables in Practice — Adding Rules, NAT, and Port Forwarding
A practical guide to firewall configuration with iptables, covering chain structure, inbound/outbound filtering, NAT masquerading, port forwarding, and persisting rules.
HAProxy Load Balancer: Installation, Health Checks, and Sticky Sessions
A step-by-step practical guide to HAProxy setup, covering round-robin and least-connections algorithms, health checks, sticky sessions, and SSL termination.
Advanced Nginx Operations — Load Balancing · Caching · Rate Limiting · Security Headers
A deep-dive guide to taking full control of production Nginx — covering upstream load-balancing strategies, proxy_cache content caching, limit_req rate limiting, and security headers.
Complete DNS Record Guide — Configuring A, CNAME, MX, TXT and Using dig
A practical rundown of each DNS record type, how to configure them, and how to diagnose DNS issues yourself with the dig command.
Diagnosing Network Status with ss, netstat, and tcpdump
A practitioner-focused rundown of Linux network diagnostics—from checking listening ports and inspecting connection state to capturing packets with the core tools.
UFW Firewall on Ubuntu: Opening Ports, Allowing Specific IPs, and Keeping SSH Access Safe
A practical guide to Ubuntu UFW: opening and closing ports, allowing specific IPs, logging, and checking firewall status.
Issuing a Free HTTPS SSL Certificate with Let's Encrypt
How to issue a free SSL certificate for your domain with Certbot, apply it to Nginx, and set up automatic renewal.
Nginx Web Server Basics and Reverse Proxy
A practical guide covering Nginx installation, static file serving, reverse proxy, and load balancing so you can apply the settings immediately in production.