We are planing to open port 80 as the autorenewal cron job was failing due to port 80 was closed.
We have descided to open port 80 only for certbot, since certificate gets renewed from https://acme-v02.api.letsencrypt.org/ and once we tried to reach the same site via ping we got the IP to be 172.65.32.248
We are planing to open the port only for IP 172.65.32.248, will the IP change in future
Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
Let’s Encrypt validates from 3 different IP addresses out of their pool of many. These can change frequently and without notice.
You have to allow all addresses to reach your server, however you can restrict that to the .well-known/acme-challenge/ directory
EDIT: I should note this is only if you want to use HTTP validation, you can use DNS01 without allowing external access to the server. Provided your ACME client and DNS provider supports it.