Recently I moved my Dell Server from one location to another, with a completely different Router. Its Main OS/VM Manager is Proxmox VE 5.3. I got an Nginx VM that is Reverse Proxying several other VMs.
After configuring my new Router, I got several of my VMs to connect to the Internet (setting the same Private IPs to the same MAC Addresses, and opening the same ports for the same Private IPs). However, with my Discourse VM, I am receiving 502 Bad Gateway - nginx/1.14.0 (Ubuntu) when trying to access Discourse in a Browser.
In the past, it was usually through the Discourse software that I could fix the problem ... but not so this time. Please read here for more details: https://meta.discourse.org/t/502-bad-gateway-nginx-1-14-0-ubuntu-unable-to-find-image-locally-error-response-from-daemon/133392
I've basically hit a point where I believe the issue is with the configuration of the Nginx VM. Recently I've tried renewed the SSL Certificates (using Let's Encrypt) for all my sites on Nginx, hoping it would fix the problem ... but it didn't. However, I checked the Nginx Error Log and found a message being reported over and over again:
> root@ngx:/etc/nginx/sites-available# less /var/log/nginx/error.log
> 2019/11/17 06:01:24 [error] 23646#23646: *37 connect() failed (111: Connection refused) while connecting to upstream, client: 1.2.3.4, server: discourse.domainame.com, request: "GET / HTTP/2.0", upstream: "http://5.6.7.8:8080/", host: "discourse.domainame.com"
* 1.2.3.4 = My Old Public IP Address
* 5.6.7.8 = My New Public IP Address
It looks to me like Nginx is trying to connect this site using my Old Public IP Address. That is definitely incorrect.
My /etc/nginx/sites-available CONF file for the Discourse Site can be found in THIS link: https://pastebin.com/fiiyATeP
* 192.168.0.101 = Nginx VM
* 192.168.0.104 = Discourse VM
------------------------------------------------------------------------------------------------------------------------------------------------------------
So my question is: How can I tell Nginx to connect discourse.domainname.com to my New Public IP Address 5.6.7.8?