Serving multiple domains on a single IP

Serving Multiple Domains on a Single IP with Linux Bash

For many businesses and independent developers, hosting multiple domains from a single server and IP address is an efficient, cost-effective solution. By utilizing the power of Linux and Bash, managing this setup can be straightforward, providing a smooth path to handle multiple websites on a single machine. Here’s how you can achieve this with some simple configurations and scripts.

What You Need

To begin, ensure your server is running a Linux OS and has Apache or Nginx installed. These are the most popular web servers that can manage multiple domains (also known as virtual hosts) on one server. You will also need sudo or root privileges to make the necessary configurations.

Step 1: Configure Your Web Server

For Apache:

Navigate to your Apache configuration directory, typically found in /etc/apache2/.
Open the sites-available directory, where you will store all your virtual host files.
Create a new configuration file for each domain. For instance: bash sudo nano example.com.conf
Insert the following configuration, adjusting for your domain and document root: apache <VirtualHost *:80> ServerAdmin webmaster@example.com ServerName example.com ServerAlias www.example.com DocumentRoot /var/www/example.com ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost>
Enable the site and reload Apache to apply changes: bash sudo a2ensite example.com.conf sudo systemctl reload apache2

For Nginx:

Go to the Nginx configuration directory, usually in /etc/nginx/.
In the sites-available directory, create a server block file for each domain: bash sudo nano example.com

Add the following configuration, again adjusting as necessary:

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

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

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

Link your configuration file in the sites-enabled directory to enable it, and then test and reload Nginx: bash sudo ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/ sudo nginx -t sudo systemctl reload nginx

Step 2: Update DNS Settings

For each of your domains, you’ll need to update DNS settings so the domain names point to your server’s IP address. This is typically handled in your domain registrar’s control panel, setting A records to point to your server.

Step 3: Automate with Bash Scripts

To streamline processes, you can use Bash scripts for tasks like adding new domains or performing backups. Here’s a simple script to add a new domain on Apache:

#!/bin/bash
# Script to add a new virtual host on Apache

DOMAIN=$1
ROOT_PATH=$2
CONFIG_PATH="/etc/apache2/sites-available/$DOMAIN.conf"
DOC_ROOT="/var/www/$DOMAIN"

# Create document root directory
mkdir -p $DOC_ROOT

# Create a sample index.html file
echo "<html><body><h1>Welcome to $DOMAIN</h1></body></html>" > $DOC_ROOT/index.html

# Create virtual host file
echo "<VirtualHost *:80>
    ServerAdmin webmaster@$DOMAIN
    ServerName $DOMAIN
    ServerAlias www.$DOMAIN
    DocumentRoot $DOC_ROOT
    ErrorLog \${APACHE_LOG_DIR}/error.log
    CustomLog \${APACHE_LOG_DIR}/access.log combined
</VirtualHost>" > $CONFIG_PATH

# Enable site and reload Apache
sudo a2ensite $DOMAIN.conf
sudo systemctl reload apache2

echo "$DOMAIN has been added."

Conclusion

Hosting multiple domains on a single IP with Linux and Bash is not only feasible but also manageable with the correct setup and scripts. By carefully configuring your web servers and utilizing straightforward Bash scripts, you can efficiently manage multiple websites, making updates and maintenance tasks quite simple. This approach not only saves on hardware and IP costs but also simplifies administration, allowing you to focus more on content and less on configuration.