I’ve used IPs for most of my home networking for a while. At one point (years ago) I ran a Windows DNS server, but I’ve banished Windows and Linux DNS is extra work. Plus, systemd makes DNS on Linux painful.
A couple of things have changed recently. First, I’ve played with some server applications such as NextCloud that expect to be in a named environment. Second, Pi-Hole has made running a home DNS server much, much, easier.
That raises the question -
The easy part is what you should NOT do. Don’t invent or re-use a name that is potentially valid on the public Internet. Calling my home network “stewart.com” will prevent accessing the real public .com address from my local network. Automated processes that use the namespace might accidentally send traffic to “real” stewart.com if my local DNS goes down or if I travel with a home laptop. Further, any blacklists that impact the “real” domain might be applied to my traffic.
About ten years ago, it was common to see examples that used “.local” for private domains. Microsoft recommended it for a while as well. The big issue here was that Bonjour/Rendezvous/Multicast DNS use that namespace and could cause a conflict.
I own two domains - nextpertise.net and stewart.tc. A second option would be to use one of my domains internally. When at home, my local server would resolve “local” names and outside my network the resolution goes to a public DNS with a different set of names. This gets a little problematic with overlapping names. For instance, if my public website changes IP then I have to manually update my internal DNS. Also, it can be confusing trying to figure out what is responding when names overlap. Still, this is manageable and does work.
A version of this would be to use a subdomain like local.stewart.tc. My home web server would be www.local.stewart.tc and the name spaces would be distinct. When outside the network, that subdomain just doesn’t resolve. This isn’t confusing. If you have a domain, this isn’t a bad option.
If you don’t have a public domain, there are some reserved namespaces taht won’t be used on the public internet that could be considered.
The RFC 6762 names tend to get used in businesses, so could conflict with your work VPN. RFC 8375 calls out that there are conflicting uses of “.home” and so updates that to .home.arpa. The .arpa top level domain is reserved for technical uses and there isn’t a way a register a conflicting domain. .home.arpa is reserved for private use, so it’s a slightly better choice than the 6762 names.
I chose to use the .home.arpa space when setting up the house in pi-hole and experienced no issues. As I mentioned earlier, subdomains using a domain I own would have worked as well.