IP Based Virtual Hosting

IP-based virtual hosting means hosting multiple websites on the same server, where each website has its own IP address.

NGINX decides which site to serve based on the destination IP address of the request, not the domain name (Host header).

One IP = One website (or one main virtual host)

How IP-Based Virtual Hosting Works

Request flow

1. User types: http://example.com
2. DNS resolution: example.com → 192.0.2.10
3. Browser connects to: 192.0.2.10:80
4. NGINX:
   • Checks which server block is listening on 192.0.2.10
   • Serves the matching virtual host

Another site might use:

shop.com → 192.0.2.20

Same server, different IP, different site.

Key Directives Used

Directive	Purpose
server {}	Defines a virtual host
listen IP:PORT	Binds server block to a specific IP
server_name	Optional (not required for routing)
root	Website document root

In IP-based hosting, listen is the key directive, not server_name.

Basic Example: Two Websites, Two IPs

Website	IP Address
example.com	192.0.2.10
shop.com	192.0.2.20

Both sites run on the same NGINX server, but each has its own IP.

http {

    server {
        listen 192.0.2.10:80;

        root /var/www/example;
        index index.html;

        location / {
            try_files $uri $uri/ =404;
        }
    }

    server {
        listen 192.0.2.20:80;

        root /var/www/shop;
        index index.html;

        location / {
            try_files $uri $uri/ =404;
        }
    }
}

1. listen IP:PORT

   listen 192.0.2.10:80;

   • NGINX listens only on this IP
   • Requests to any other IP will not match this server block

   listen 192.0.2.20:80;

   • Separate IP → separate virtual host

2. server_name (Optional) In IP-based hosting, server_name is not required:

   server_name example.com;

   • Can still be added for:
     • Logging clarity
     • HTTPS SNI
     • Readability
   • But routing is done by IP

3. Request Routing

Request	IP Used	Served From
http://example.com	192.0.2.10	/var/www/example
http://shop.com	192.0.2.20	/var/www/shop

Even if both domains are typed, IP determines the site.

IP-Based Virtual Hosting with HTTPS

Before SNI, SSL required one IP per certificate, making IP-based hosting necessary.

server {
listen 192.0.2.10:443 ssl;

    ssl_certificate /etc/ssl/example.crt;
    ssl_certificate_key /etc/ssl/example.key;

    root /var/www/example;

}

Each site:

• Has its own IP
• Has its own SSL certificate

Combining IP-Based and Name-Based Hosting

You can mix both approaches.

server {
listen 192.0.2.10:80;
server_name example.com www.example.com;

    root /var/www/example;

}

• IP chooses the server
• server_name refines domain handling

Default Server in IP-Based Hosting

server {
listen 192.0.2.10:80 default_server;
return 444;
}

• Handles unmatched requests on that IP
• Improves security and clarity

Advantages of IP-Based Virtual Hosting

• Complete isolation between sites
• Required for legacy SSL clients
• Easier firewall and access control
• Useful for compliance and security

Disadvantages

• Requires multiple IP addresses
• Higher cost in cloud environments
• Less scalable than name-based hosting

When to Use IP-Based Virtual Hosting

Use Case	Recommendation
Legacy SSL support	✅ IP-based
Strong isolation/security	✅ IP-based
Shared hosting	❌ Avoid
Cloud servers	⚠️ Use only if needed

Name-Based vs IP-Based

Use Case	Recommendation
Legacy SSL support	✅ IP-based
Strong isolation/security	✅ IP-based
Shared hosting	❌ Avoid
Cloud servers	⚠️ Use only if needed