|
@Metapath
Port 80 is a standard port for http, so it's usually open, though a router may, as already mentioned, have closed it, particularly if you are on a LAN (which most of us are these days with desktops, tablets and phones).
As Let's Encrypt states: When you get a certificate from Let's Encrypt, our servers validate that you control the domain names in that certificate using "challenges," as defined by the ACME standard. Most of the time, this validation is handled automatically by your ACME client....
In other words, Certbot must be installed on the system you want a certificate for and, in the process of getting it, Certbot will verify that said system's IP address corresponds to the one you are applying for (i.e. you cannot do it for a computer you don't control). The line of communication between your system and Let's Encrypt servers is (at least initially) through port 80.
Cheers!
|