At the moment I am currently using Cloudflare as a way to provide SSL to my self-hosted site. The site sits behind a residential connection that blocks incoming data on commonly used ports including 80 and 443. It’s a perfectly fine and reasonable solution which does what I want. But I’m looking to try something different.

What I would like to try is using Let’s Encrypt on a non standard port. I understand there are plenty of good reasons not do this, mainly that some places such as workplaces may block higher number ports for security reasons. That’s fair but I am still interested in learning how to encrypt uncommon ports with Let’s Encrypt.

Currently I am using Nginx Proxy Manager to handle Let’s Encrypt certificates. It’s able to complete the DNS Challenge required to prove I own the domain name and handles automated certificate renewals as well. Currently I have NPM acting as a reverse proxy guiding outside connections from Cloudflare on port 5050 to port 80 on NPM. Then the connection gets sent out locally to port 81 which is the admin web page for NPM (I’m just using it as a page to test if the connection is secured).

Whenever I enable Let’s Encrypt SSL and try to connect to my site, the connection times out and nothing happens. I’m not sure if Let’s Encrypt is expecting to reach ports 80/443 or if there is something wrong with my reverse proxy settings that breaks the encryption along the way. Most discussions just assume ports 80/443 are open which is fair since that’s the most common situation. The few sites discussing the use of uncommon ports are either many years dated or people talking about success without sharing any details. I’m sort of at the end of what I can search at this point.

What I’m hoping to learn out of all this is how encryption and reverse proxies work together because those two things have been a struggle for me to understand as a whole throughout this whole learning process. I would appreciate it a lot of anyone had any resources or experiences to share about this.