But i am confused since most guides say to add your domain but i log in via an ip address that we set on the firewall itself that isnt the same as my domain i believe.
How do i get this firewall secured? Is it different securing a firewall than a domain website?
i see, thanks. any suggestions on how i can get this firewall secured? I always only see guides for websites not firewalls. any help is appreciated! thanks
You probably want to give your firewall a domain name. Like, if your company is example.com, add a record for firewall.example.com to DNS for the IP for the firewall, and then you can use a name instead of IP to connect. At that point, ideally there would be something built-in that can automatically get a certificate from an ACME server like Let's Encrypt, though that support document you linked looks like something designed for a old-fashioned non-automatable process instead.
Another option, if the use case is only to connect to it from a small number of private systems (rather than on the public Internet), is to use your own private CA instead. If your current message is just "ERR_CERT_AUTHORITY_INVALID", that implies that it is already serving some sort of certificate. So you may just need to load the root that it's using into your systems' trust store, or (if that's not the private root you want to use) use that procedure you linked to generate a long-duration certificate signed by the private CA that you do want to use.