Running a Reverse Proxy Server with Localtunnel

Reverse proxying services like ngrok or serveo allow you to forward traffic from a public domain to a local development machine. While those services are very helpful for certain development activities, they can also be abused by mischievous scammers. Because of this many of the free options (like serveo) have shut down service due to the overwhelming amount of fraudulent activity leaving one provider in the space: Ngrok. Ngrok is a solid product, but if you desire to run and control your own reverse proxy you’ve come to the right place!

In this guide, we will discuss how to setup your own reverse proxy using an open-source reverse proxy called localtunnel, ubuntu, and nginx.

Prerequisites

• Provision a cloud virtual instance or local server with Ubuntu 18.04 LTS

Setup DNS Records

Configure two A records for your domain:

If you are using this on your primary domain:

• An A record pointing from yourdomain.tld to your server IP
• An A record pointing from *.yourdomain.tld to your server IP

If you are using this on a subdomain (double subdomaining):

• An A record pointing from tunnel.yourdomain.tld to your server IP
• An A record pointing from *.tunnel.yourdomain.tld to your server IP

Installing Nginx and Node

Connect to a terminal session on your server or instance.

To install Nginx, use following command:

sudo apt update
sudo apt install nginx nodejs npm

Setting up localtunnel

Navigate to the following directory and clone the localtunnel repo:

cd /var/www/html/
git clone https://github.com/localtunnel/server
cd server/
npm install
sudo npm install -g esm

There is currently a problem in localtunnel server that causes explicitly requested subdomains to fail to release on disconnection. Since you are running your server, you can make the following changes to the lib/ClientManager.js file starting at line 36.

NOTE: If you make the change below, anyone who requests a specific subdomain will be granted it, even if it is currently in use. Ensure that your team does not accidentally (or intentionally) steal someone else’s subdomain.

Setup Nginx

Configure nginx using the following files from the nginx localtunnel repo:

sudo systemctl enable nginx
sudo systemctl start nginx
sudo systemctl status nginx

In /etc/nginx/nginx.conf comment out the line that says

include /etc/nginx/sites-enabled/*;

If you encounter this error: nginx.service: Failed to read PID from file /run/nginx.pid: Invalid argument when starting nginx checkout this link for a description and fix of the issue.

Setup SSL Certs

Setup your site.conf file using the commands below:

cd /etc/nginx/conf.d
sudo curl -LJO https://raw.githubusercontent.com/localtunnel/nginx/master/site.conf

Follow the tutorial below to setup SSL certs for your subdomain. When your certs are issued you will need to update the ssl_certificate and ssl_certificate_key fields in the site.conf file with the path of your newly generated certs (which will be given to you by the certbot cli).

How to obtain a wildcard ssl certificate from Let’s Encrypt and setup Nginx to use wildcard…

Setup systemd

Install the proxy service with:

cd /etc/systemd/system
sudo curl -LJ0 https://gist.githubusercontent.com/alexbeattie42/d0255d07a7b9e18d6eb77ec88c946b91/raw/730b85f6b51e1f6e2e8fe2dbf299f1e5a44ee3b6/proxy.service > proxy.service
sudo systemctl daemon-reload

Below is what the proxy.service file looks like.

IMPORTANT: Change the --domain flag value on line 11 to your own domain!

Enable and start the services

Reload and Enable services and check their statuses:

sudo systemctl enable nginx
sudo systemctl start proxy
sudo systemctl restart nginx
sudo systemctl status proxy
sudo systemctl status nginx

Connect to the proxy

Run the following command from your machine to connect to the proxy from your local machine:

# Install localtunnel
npm install -g localtunnel
# Running localtunnel:
#   --port = the port your local application is running on
#   --subdomain (optional) = the subdomain you'd like to be issued 
 
lt --host http://tunnel.domain.tld --subdomain=my-app --port=8000

You will be issued an https URL from executing the final command, which you can use to access your local application!

As ever, QuarkWorks is available to help with any software application project — web, mobile, and more! If you are interested in our services you can check out our website. We would love to answer any questions you have! Just reach out to us on our Twitter, Facebook, LinkedIn, or Instagram.

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