Hi everyone! I’m looking to run a Mastodon instance on a home server, entirely within LAN, without owning a domain. It does not need to interact with other Mastodon instances, but users on the local server should still be able to follow accounts on other Mastodon servers. Local users should also be able to create posts and see each other’s posts on the local instance. I’d appreciate advice from anyone running Mastodon this way at home. Thanks!
Adding to why it has to be reachable: when a local user follows someone on another server, that server pushes new posts to your server’s inbox, so the remote side has to be able to resolve your domain and connect over HTTPS. A LAN-only box can’t receive that.
The least painful compromise is a cheap domain (or a subdomain you control) plus a tunnel or a small VPS acting as reverse proxy, so nothing on your home network is exposed directly. Then close signups so only your household can register. If Mastodon feels heavy for a handful of users, GoToSocial is much lighter on RAM for that use case, though you’d use a separate client app with it.
One thing to decide up front: the domain is baked into every account and can’t be changed later without starting over.