? about Hostname - Domain - Common Name - Subject Alternate Names

[snorkleboy13]

I'm running TrueNAS-13.0-U1.1. The system was upgraded from FreeNAS. All is/was working well. I received a notification that my default certificate has expired and am trying to create a new one.

This system is in use at my home and it is not accessed by anything outside of my home LAN .

I'm not clear on the right way to create the new certificate. Here's the info and my questions:

Hostname: freenas
Domain: local

What are the correct names I should use for COMMON NAME and SUBJECT ALTERNATE NAMES when creating the new certificate?

Thanks in advance

 

[Johnny Fartpants]

COMMON NAME is your FQDN so for example truenas.ads.google.com and SUBJECT ALTERNATE NAMES are for Multi Domain configs so if your server is operating across more than one domain. This second field is optional.

 

[snorkleboy13]

COMMON NAME is your FQDN so for example truenas.ads.google.com and SUBJECT ALTERNATE NAMES are for Multi Domain configs so if your server is operating across more than one domain. This second field is optional.

Yes, I read that information while doing research. However it doesn't answer my question.
1) How do I determine what my FQDN is? As I mentioned my system can't be accessed by anyone outside of my home LAN.
2) SUBJECT ALTERNATE NAME is not optional. (I've selected Internal CA for Type.)