I host my own domain. For ssl purposes, I’d like to use a Let’s Encrypt certificate. To do that, I believe I need Home Assistant OS (haos) to use a fqdn (fully qualified domain name). How can I change the address of my homeassistant front end from homeassistant.local to homeassistant.domain.com?
Thanks.
You need to review at the multiple threads about securely exposing your HA instance to the open internet. It’s not as simple as opening a port and turning it on. (read: do not open 443 to your unsecured HA instance and call it a day, and SSL by itself does not security make.)
You can use VPNs, reverse proxies. Services like CloudFlare or NabuCasa.
Each offers thier own pros/cons for your needs (personally I use Nabu Casa) but each has its own requirements. If you already own your own domain you’re probably looking at a reverse proxy option but in that case it’s about putting something between HA and the open Internet not reconfiguration of HA to open the front door.
So if you’re selfhosting how do you host your other stuff.
Settings >> System >> Network then scroll down to “Home Assistant URL” and use your domain as needed in the “Internet” field.
Per above comments, depending how you set up your domain and/or reverse proxy, you may need to update your config yaml file - the http section.
.local is the domain of mDNS, so that will still be there.
You can just add your own domain to that, because a domain is really just a translation from a text address (URL) to an IP address.
In order for that translation to succeed you need to have access to some DNS servers.
You can run your “private” DNS servers on the internal network and have others on the internet.
The usage of a domain name does really not require you to open any ports, because ports are unrelated to this functionality.
Using .local in internal networks has been frowned on for a long time as not best practice.
Microsoft actually recommend using .ad.domain.com for companies using domains.
I am reading this thread I feel that there needs to be a way to change the internal “domain” extension for mDNS resolution. Not everyone is using .local internally, and not everyone is exposing it to the internet. Although I have a domain name, I use Nabu Casa cloud for external, and my internal domain extension is .internal.mydomain.com and not .local I don’t actually use an internal dns server, other than UniFi’s newer DNS feature, but all my other devices allow me to change the domain extension
.local is reserved for mDNS globally, which is why it should not be used with DNS.
It is hardcoded in the mDNS protocol.
The domain name that can be set in many devices is the DNS domain name that is used when auto-registering DNS settings on a DNS service, like the one many routers run when they run both DHCP and DNS service for the network.
You’re confusing two similar but different techs… MDNS is Not DNS. There’s nothing to change for mdns.
The reason we don’t use Local is because reserving the space for mDNS. And when you don’t things start to get confused. So yes do move your own local DNS domain to something else. Have fun rename at will and have everything join it.
But for anything that uses mDNS bonjour or the like… They will continue to use mDNS (the .local namespace) no matter what your DNS on site is.
Hmmm. That’s possible, but it would be nice to change the IPv4 extension in Home Assistant, like other devices can rather than have the IPv4 address default to .local but yeah I get the difference between DNS and mDNS and it can get a bit messy when the two get confused.
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I was under the impression Home Assistant primarily used mDNS on IPv6 rather than IPv4, but I may be wrong there.
I was toying with the idea of a local DNS server anyway, as the basic Unifi one is not really that great
Ive not been disappointed if I assume this ^ full stop (note no distinction between IPv4 and IPV6) no matter what version. I assume IPv4 behaves this way and IPv6 as an extension to whatever 4 does - with the added benefit of being able to host a Matter network. 
In either case.
ALL issues are name resolution issues until proven otherwise. (So sayeth 20 yr directory services engineer… Yes I will put my stamp on that one it’s never been proven wrong.)
mDNS is not replacing DNS. It is running together with DNS.
It is definitely running in IPv4 and I also think on IPv6, but I have sort of given up on IPv6 on HA for the moment, because it is truly lacking basic features.
mDNS is used a lot in documentation, but that is because the mDNS address is locally findable, so a link can be created for the documentation. That same thing is not possible with DNS.