IPv4 address is becoming rarer by each day. In some cases, it can be pretty hard to get multiple IPv4 address for your Proxmox server.

Thankfully, Proxmox is basically a Debian Linux OS with Proxmox layer on top of that. So that gives us quite a lot of flexibility.

This tutorial will help you to create a fully functional Proxmox server running multiple containers & virtual machines, using only a single IPv4 address.

These are the main steps :

1. Create port forwarding rules
2. Make sure it’s executed automatically everytime the server is restarted
3. Setup a reverse-proxy server : to forward HTTP/S requests to the correct container / virtual machine
4. Setup HTTPS

For CT (container) / VM (virtual machine) that contains webserver, point 3 is important – because there’s only one public IP address, so there’s only one port 80 and 443 that’s facing the Internet.

By forwarding port 80 and 443 to a reverse-proxy in a CT, then we’ll be able to forward incoming visitors, by hostname / domain name, to the correct CT/VM.

1. CREATE PORT FORWARDING RULES

Modify the following to match your host’s interface name & CT/VM’s internal IP addresses, then copy-paste to terminal :

###### All HTTP/S traffic are forwarded to reverse proxy
iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 80 -j DNAT --to 10.10.50.1:80

iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 443 -j DNAT --to 10.10.50.1:443

###### SSH ports to each existing CT/VM
iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 22101 -j DNAT --to 10.10.50.1:22

iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 22102 -j DNAT --to 10.10.50.2:22

iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 22103 -j DNAT --to 10.10.50.3:22

iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 22104 -j DNAT --to 10.10.50.4:22

Then we save it :

iptables-save > /etc/iptables.rules

2. EXECUTE IPTABLES AT SERVER RESTART

Edit /etc/network/interfaces file, find your network interface name that’s facing the Internet (in my case, vmbr0) – then add the pre-up line as follows :

auto vmbr0
pre-up iptables-restore < /etc/iptables.rules

3. SETUP REVERSE-PROXY

In a CT, install Nginx. Then for each domain, create a configuration file like this, for example: /etc/nginx/sites-available/www.my_website.com :

server {
listen 80;
server_name www.my_website.com;

location / {
    proxy_pass http://10.10.50.2:80;
    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;
}

}

To activate it (assuming you’re using Ubuntu) link it to /etc/nginx/sites-enabled/ , then restart Nginx :

ln -s /etc/nginx/sites-available/www.my_website.com /etc/nginx/sites-enabled/www.my_website.com

/etc/init.d/nginx restart

note: as noted before, all HTTP/s traffic will have to go through this reverse-proxy. You may wish to tune this Nginx installation accordingly.

4. SETUP HTTPS

It’s very easy with Let’s Encrypt once you’ve done point 3 above. Do the following on the reverse-proxy CT :

sudo apt-get update ; sudo apt-get install -y certbot python3-certbot-nginx

sudo certbot --nginx

sudo /etc/init.d/nginx restart

Reference:

https://gist.githubusercontent.com/basoro/b522864678a70b723de970c4272547c8/raw/a985657453f72683040fbe38b1db6b1989618116/proxmox-proxy