I have the following scenario:
There is one IP where serveral Servers are running services which are reached via natting. I have 1 webserver which needs to have all traffic to ports 80 and 443 forwarded. Also I have one mail server. The mail server needs a Cert. Also it needs to be configured for automatic renewal. Since port 443 is used by another forwarding rule, I can not see how I could use this port again. The only solution as far as I can see is to know the IP range of Letsenrypt and use it to only forward these packages to the mail server. Is there any known IP range which wont change? Or is it possible to use another port or does anybody see a better solution for this?
Thank you for help,