# Reverse Proxy Setup with NGINX and BIND on Alpine Linux

This setup should give you a basic reverse proxy configuration using NGINX and a DNS server using BIND on Alpine Linux.

## Table of Contents

- [Reverse Proxy Setup with NGINX and BIND on Alpine Linux](#reverse-proxy-setup-with-nginx-and-bind-on-alpine-linux)
  - [Table of Contents](#table-of-contents)
  - [Introduction](#introduction)
  - [Prerequisites](#prerequisites)
  - [Steps](#steps)
    - [Step 1: Install Required Packages](#step-1-install-required-packages)
    - [Step 2: Configure BIND DNS Server](#step-2-configure-bind-dns-server)
      - [Edit the BIND Configuration](#edit-the-bind-configuration)
      - [Define Your Zone](#define-your-zone)
      - [Create Zone File](#create-zone-file)
      - [Start BIND](#start-bind)
    - [Step 3: Configure NGINX as a Reverse Proxy](#step-3-configure-nginx-as-a-reverse-proxy)
      - [Edit NGINX Main Configuration](#edit-nginx-main-configuration)
      - [Create Server Block Configuration](#create-server-block-configuration)
      - [Set the Webroot Directory](#set-the-webroot-directory)
      - [Start NGINX](#start-nginx)
    - [Step 4: Adjust Firewall Rules (if necessary)](#step-4-adjust-firewall-rules-if-necessary)
  - [Summary of Important Configuration File Locations](#summary-of-important-configuration-file-locations)
  - [Final Notes](#final-notes)

## Introduction

Setting up a reverse proxy with NGINX as the HTTP server and BIND as the DNS server on Alpine Linux involves several steps. Below is an outline of the setup, including important configuration file locations.

## Prerequisites

- Alpine Linux installed
- Root access or sudo privileges

## Steps

| #   | Step                               | Description                                       |
| --- | ---------------------------------- | ------------------------------------------------- |
| 1   | Install Required Packages          | Install NGINX and BIND                            |
| 2   | Configure BIND DNS Server          | Edit BIND configuration and create zone file      |
| 3   | Configure NGINX as a Reverse Proxy | Create a server block configuration for your site |
| 4   | Adjust Firewall Rules              | Allow traffic on ports 80 (HTTP) and 53 (DNS)     |

### Step 1: Install Required Packages

First, you need to install NGINX and BIND. Open your terminal and run the following command:

```bash
apk add nginx bind
```

### Step 2: Configure BIND DNS Server

BIND will serve as your DNS server. The main configuration file is usually located at `/etc/bind/named.conf`.

#### Edit the BIND Configuration

```bash
vi /etc/bind/named.conf
```

#### Define Your Zone

Add a zone definition for your domain. For example:

```bash
zone "example.com" {
    type master;
    file "/etc/bind/db.example.com";
};
```

#### Create Zone File

Create a zone file for your domain:

```bash
vi /etc/bind/db.example.com
```

Sample content for `db.example.com`:

```dns
$TTL 86400
@   IN  SOA     ns.example.com. admin.example.com. (
        2024102701 ; Serial
        3600       ; Refresh
        1800       ; Retry
        604800     ; Expire
        86400 )    ; Negative Cache TTL

@       IN  NS      ns.example.com.
ns      IN  A       10.0.0.1 ; Replace with your server's IP
www     IN  A       10.0.0.1 ; Replace with your server's IP
```

#### Start BIND

Start the BIND service and enable it to run on boot:

```bash
rc-service named start
rc-update add named
```

### Step 3: Configure NGINX as a Reverse Proxy

NGINX will act as a reverse proxy, forwarding requests to the backend server. The main configuration file for NGINX is located at `/etc/nginx/nginx.conf`, but you should create a specific server block configuration file for your site.

#### Edit NGINX Main Configuration

```bash
vi /etc/nginx/nginx.conf
```

Ensure that the following line is included to load additional configuration files:

```nginx
include /etc/nginx/conf.d/*.conf;
```

#### Create Server Block Configuration

Create a new configuration file for your site:

```bash
vi /etc/nginx/conf.d/example.com.conf
```

Sample configuration:

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

    location / {
        proxy_pass http://10.0.0.2; # Replace with your backend server address
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}
```

#### Set the Webroot Directory

If you want to serve static files, you can set the webroot:

```nginx
location / {
    root /www; # Your web root directory
    index index.html index.htm;
}
```

#### Start NGINX

Start the NGINX service and enable it to run on boot:

```bash
rc-service nginx start
rc-update add nginx
```

### Step 4: Adjust Firewall Rules (if necessary)

If you are using a firewall, make sure to allow traffic on port 80 (HTTP) and 53 (DNS):

```bash
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p udp --dport 53 -j ACCEPT
```

## Summary of Important Configuration File Locations

- **BIND Configuration:**

  - Main config: `/etc/bind/named.conf`
  - Zone file: `/etc/bind/db.example.com`

- **NGINX Configuration:**
  - Main config: `/etc/nginx/nginx.conf`
  - Site-specific config: `/etc/nginx/conf.d/example.com.conf`
  - Webroot: `/www`

## Final Notes

- Ensure to replace `example.com` and `backend_server_address` with your actual domain and backend server address.
- After making changes, you may need to reload BIND and NGINX to apply the new configurations:

  ```bash
  rc-service named reload
  rc-service nginx reload
  ```