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diff --git a/content/blog/2022-04-02-nginx-reverse-proxy.md b/content/blog/2022-04-02-nginx-reverse-proxy.md new file mode 100644 index 0000000..493dfd3 --- /dev/null +++ b/content/blog/2022-04-02-nginx-reverse-proxy.md @@ -0,0 +1,234 @@ ++++ +date = 2022-04-02 +title = "Set-Up a Reverse Proxy with Nginx" +description = "Learn how to set-up an Nginx reverse proxy from scratch." ++++ + +## What is a Reverse Proxy? + +A reverse proxy is a server that is placed between local servers or +services and clients/users (e.g., the internet). The reverse proxy +intercepts all requests from clients at the network edge and uses its +configuration files to determine where each request should be sent. + +### A Brief Example + +For example, let's say that I run three servers in my home: + +- Server~01~ (`example.com`) +- Server~02~ (`service01.example.com`) +- Server~03~ (`service02.example.com`) + +I also run a reverse proxy in my home that intercepts all public +traffic: + +- Reverse Proxy + +Assume that I have a domain name (`example.com`) that allows +clients to request websites or services from my home servers. + +In this case, the reverse proxy will intercept all traffic from +`example.com` that enters my network and determine if the +client is requesting valid data, based on my configuration. + +If the user is requesting `example.com` and my configuration +files say that Server~01~ holds that data, Nginx will send the user to +Server~01~. If I were to change the configuration so that +`example.com` is routed to Server~02~, that same user would +be sent to Server~02~ instead. + +```txt +┌──────┐ ┌───────────┐ +│ User │─┐ ┌──► Server_01 │ +└──────┘ │ │ └───────────┘ + │ ┌──────────┐ ┌───────────────┐ │ ┌───────────┐ + ├────► Internet ├───► Reverse Proxy ├─────├──► Server_02 │ + │ └──────────┘ └───────────────┘ │ └───────────┘ +┌──────┐ │ │ ┌───────────┐ +│ User │─┘ └──► Server_03 │ +└──────┘ └───────────┘ +``` + +## Reverse Proxy Options + +There are a lot of options when it comes to reverse proxy servers, so +I'm just going to list a few of the options I've heard recommended +over the last few years: + +- [Nginx](https://nginx.com) +- [Caddy](https://caddyserver.com) +- [Traefik](https://traefik.io/) +- [HAProxy](https://www.haproxy.org/) +- [Squid](https://ubuntu.com/server/docs/proxy-servers-squid) + +In this post, we will be using Nginx as our reverse proxy, running on +Ubuntu Server 20.04.4 LTS. + +## Nginx Reverse Proxy Example + +### Local Applications + +You may be like me and have a lot of applications running on your local +network that you'd like to expose publicly with a domain. + +In my case, I have services running in multiple Docker containers within +a single server and want a way to visit those services from anywhere +with a URL. For example, on my local network, [Dashy](https://dashy.to) +runs through port 4000 (`localhost:4000`) and [Uptime +Kuma](https://github.com/louislam/uptime-kuma) runs through port 3001 +(`localhost:3001`). + +In order to expose these services to the public, I will need to do the +following: + +1. Set up DNS records for a domain or subdomain (one per service) to + point toward the IP address of the server. +2. Open up the server network's HTTP and HTTPS ports (80 & 443) so + that the reverse proxy can accept traffic and determine where to + send it. +3. Install the reverse proxy software. +4. Configure the reverse proxy to recognize which service should get + traffic from any of the domains or subdomains. + +### Step 1: DNS Configuration + +To start, update your DNS configuration so that you have an +`A` record for each domain or subdomain. + +The `A` records should point toward the public IP address of +the server. If you don't know the public IP address, log in to the +server and run the following command: + +```sh +curl ifconfig.co +``` + +In the DNS example below, `xxx.xxx.xxx.xxx` is the public IP +address of the server. + +```config +example.com A xxx.xxx.xxx.xxx +uptime.example.com A xxx.xxx.xxx.xxx +dashy.example.com A xxx.xxx.xxx.xxx +www CNAME example.com +``` + +Finally, ensure the DNS has propagated correctly with [DNS +Checker](https://dnschecker.org) by entering your domains or subdomains +in the search box and ensuring the results are showing the correct IP +address. + +### Step 2: Open Network Ports + +This step will be different depending on which router you have in your +home. If you're not sure, try to visit +[192.168.1.1](http://192.168.1.1) in your browser. Login credentials are +usually written on a sticker somewhere on your modem/router. + +Once you're able to log in to your router, find the Port Forwarding +settings. You will need to forward ports `80` and +`443` to whichever machine is running the reverse proxy. + +In my case, the table below shows the port-forwarding rules I've +created. In this table, `xxx.xxx.xxx.xxx` is the local device +IP of the reverse proxy server, it will probably be an IP between +`192.168.1.1` and `192.168.1.255`. + + NAME FROM PORT DEST PORT/IP ENABLED + ------- ------ ------ ----------------- --------- + HTTP \* 80 xxx.xxx.xxx.xxx TRUE + HTTPS \* 443 xxx.xxx.xxx.xxx TRUE + +Once configured, these rules will direct all web traffic to your reverse +proxy. + +### Step 3: Nginx Installation + +To install Nginx, simply run the following command: + +```sh +sudo apt install nginx +``` + +If you have a firewall enabled, open up ports `80` and +`443` on your server so that Nginx can accept web traffic +from the router. + +For example, if you want to use `ufw` for web traffic and +SSH, run the following commands: + +```sh +sudo ufw allow 'Nginx Full' +sudo ufw allow SSH +sudo ufw enable +``` + +### Step 4: Nginx Configuration + +Now that we have domains pointing toward the server, the only step left +is to configure the reverse proxy to direct traffic from domains to +local services. + +To start, you'll need to create a configuration file for each domain in +`/etc/nginx/sites-available/`. They will look identical +except for the `server_name` variable and the +`proxy_pass` port. + +Dashy: + +```sh +nano /etc/nginx/sites-available/dashy.example.com +``` + +```config +server { + listen 80; + server_name dashy.example.com; + + location / { + proxy_pass http://localhost:4000; + } +} +``` + +Uptime: + +```sh +nano /etc/nginx/sites-available/uptime.example.com +``` + +```config +server { + listen 80; + server_name uptime.example.com; + + location / { + proxy_pass http://localhost:3001; + } +} +``` + +Once the configuration files are created, you will need to enable them +with the `symlink` command: + +```sh +sudo ln -s /etc/nginx/sites-available/dashy.example.com /etc/nginx/sites-enabled/ +``` + +Voilà! Your local services should now be available through their URLs. + +## HTTPS with Certbot + +If you've followed along, you'll notice that your services are only +available via HTTP (not HTTPS). + +If you want to enable HTTPS for your new domains, you will need to +generate SSL/TLS certificates for them. The easiest way to generate +certificates on Nginx is [Certbot](https://certbot.eff.org): + +```sh +sudo apt install snapd; sudo snap install core; sudo snap refresh core +sudo snap install --classic certbot +sudo ln -s /snap/bin/certbot /usr/bin/certbot +sudo certbot --nginx +``` |