Infrastructure Fundamentals

This documentation covers the core concepts required to host websites and services. It focuses on the relationship between hardware (servers), accessibility (ports/IPs), and traffic management (proxies/tunnels).

Servers & Hosting Architectures

A server is strictly defined as a computer providing data to other computers. In a web context, this usually involves a Linux-based OS running daemon processes (like Nginx, Apache, or Docker containers).

Deployment Hierarchy

Choosing a hosting environment depends on access requirements and technical overhead.

Reverse Proxies

A reverse proxy sits in front of your application servers. It intercepts requests from clients and forwards them to the appropriate backend service.

Key Functions

• Load Balancing: Distributing traffic across multiple servers.
• SSL Termination: Decrypting HTTPS traffic before it reaches the app.
• Security: Hiding the identity/topology of backend servers.

Nginx Configuration Example

A standard block configured to forward port 80 traffic to a Node.js application running on port 3000.

server {
    listen 80;
    server_name api.example.com;

    location / {
        proxy_pass http://localhost:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
}

Tunneling

Tunneling encapsulates a network protocol within another. It is frequently used to bypass NAT (Network Address Translation) or firewalls, allowing a machine without a public IP address to be accessible from the internet.

Common Implementation: SSH Reverse Tunnel

Forward a port on a remote public server to a local port.

# Syntax: ssh -R [remote_port]:[local_host]:[local_port] user@remote
ssh -R 8080:localhost:80 user@vps.example.com

Result: Traffic hitting vps.example.com:8080 is routed to your local machine's port 80.

Cloudflare Tunnel (cloudflared)

A daemon-based approach where the server establishes an outbound connection to the Cloudflare edge network. This eliminates the need to open inbound ports on the router firewall.

Ports, NAT, and Firewalls

Network communication relies on IP addresses (location) and Ports (specific service at that location).

The "Well-Known" Ports (0-1023)

System ports reserved for standard services. On Linux, binding to these ports typically requires root privileges.

DNS Records

The Domain Name System maps human-readable names to IP addresses. Incorrect DNS configuration is the most common cause of downtime.

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