Web Server Installation and Virtual Hosts

What Is a Web Server?

A web server is software that listens for incoming HTTP requests on a network port and responds with files — HTML pages, images, stylesheets, scripts — or passes the request to an application back-end. Nginx (pronounced "engine-x") is a high-performance, open-source web server widely used in production environments. It handles static files efficiently and is a common choice for hosting websites on Linux virtual private servers (VPS).

In this lab you will install Nginx on a Linux VPS, configure it to serve a test site using a server block (Nginx's term for a virtual host), and confirm the site responds on port 80 — the default port for unencrypted HTTP traffic.

Safety and Access Considerations

Before you begin, two operational safety points apply:

1. Principle of Least Privilege. Use `sudo` only for commands that require elevated permissions (package installation, service control, writing to `/etc/nginx/`). Do not work as the root user for your entire session.

2. Firewall awareness. Opening port 80 to the internet is intentional here, but always know which ports you are exposing. On a production server you would also configure HTTPS (port 443) and restrict other ports. For this lab, confirm your VPS firewall (such as `ufw`) allows port 80 before testing.

Installing Nginx with apt

Debian-based distributions (including Ubuntu, which most student VPS instances run) use the apt package manager. Installing Nginx is a two-step process: update the local package index, then install.

```bash

sudo apt update

sudo apt install nginx -y

```

After installation, enable the service so it starts automatically on reboot, then start it immediately:

```bash

sudo systemctl enable nginx

sudo systemctl start nginx

```

Verify the service is running:

```bash

sudo systemctl status nginx

```

Look for `Active: active (running)` in the output. If you see a failure, check `/var/log/nginx/error.log` for details.

Understanding Server Blocks (Virtual Hosts)

Nginx uses server blocks to define how it handles requests for different domains or IP addresses — the equivalent of Apache's VirtualHost directive. Nginx reads configuration from `/etc/nginx/nginx.conf`, which in turn includes all files found in `/etc/nginx/sites-enabled/`.

The standard workflow is:

1. Write a configuration file in `/etc/nginx/sites-available/` (a holding area).

2. Create a symbolic link from `sites-enabled/` to that file (this activates it).

3. Test the configuration with `nginx -t`.

4. Reload Nginx to apply the changes.

This two-directory pattern lets you disable a site by removing the symlink without deleting your configuration.

Creating a Server Block

First, create a document root directory where your site's files will live:

```bash

sudo mkdir -p /var/www/mysite/html

sudo chown -R $USER:$USER /var/www/mysite/html

```

Next, create the server block configuration file:

```bash

sudo nano /etc/nginx/sites-available/mysite

```

Paste the following minimal configuration:

```nginx

server {

listen 80;

server_name YOUR_SERVER_IP;

root /var/www/mysite/html;

index index.html;

location / {

try_files $uri $uri/ =404;

}

}

```

Replace `YOUR_SERVER_IP` with your VPS's actual IP address. For a real domain name you would replace it with the fully qualified domain name (e.g., `example.com www.example.com`).

Now create the symlink and reload:

```bash

sudo ln -s /etc/nginx/sites-available/mysite /etc/nginx/sites-enabled/

sudo nginx -t

sudo systemctl reload nginx

```

The `nginx -t` command tests the configuration for syntax errors without restarting the server. Always run this before reloading. A misconfigured reload on a live server can take a site offline.

Uploading Files with scp

scp (Secure Copy Protocol) copies files over SSH. From your local machine, upload your `index.html` to the document root:

```bash

scp index.html user@YOUR_SERVER_IP:/var/www/mysite/html/

```

Replace `user` with your VPS username and `YOUR_SERVER_IP` with the actual address. Because scp uses SSH, the transfer is encrypted in transit — always prefer scp or rsync over unencrypted FTP.

After uploading, open a browser and navigate to `http://YOUR_SERVER_IP`. Your HTML page should appear. If you see the default Nginx welcome page instead, confirm that the symlink exists in `sites-enabled/` and that you reloaded Nginx after creating it.

Troubleshooting Checklist

• `systemctl status nginx` — Is the service running?
• `nginx -t` — Is the configuration syntax valid?
• `sudo ufw status` — Is port 80 allowed through the firewall?
• `ls -l /etc/nginx/sites-enabled/` — Does the symlink exist and point to the correct file?
• `cat /var/log/nginx/error.log` — Any runtime errors?

Lab Log

Record every command you run, its output, and any errors you encountered and resolved. Your instructor will review your log alongside the live browser test. Accurate logs are a professional habit and an important part of this credential portfolio.