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.
Whe I arrived to the line:
Set Up an Automatically Renewed SSL Certificate with Let’s Encrypt
Note: I’m installing the new server with another Public IPaddress
I found that I’m lost in questions like:
1- What I well do with the current cert?
2- I’m I well install a cert on the new server with the temp DNS address instead of the current?
3- Am I going to face unauthorized nightmare?
4- Can I install a new cert on the backupmail.domain.com then when I shut down current server mail.domain.com I reinstall the cert from scratch to the new server?
5- In the future, If I build mail.domain.com and backupmail.domain.com as a running backup server, How I well do it?
You can create one certificate and use it with different servers. The certificate has no information about the ip address, so you can use the same certificate with a lot of different ip addresses (backup servers).
Certificate creation -> distribute it to different servers.
But you should automate that - Letsencrypt certificates are only 90 days valid.
And your public dns entry yourdomain -> your ip is unique, so you may not be able to test it.
I’m sorry I not clear friends!
My mail server well retire soon, So I’m building another on. I understand now that I can take the cert files to the new server then run the renew as usual then add it to cronjob.