Yes, mastodon - and others like Gnu Social - can function in an isolated fashion. However, as others have noted, it seems you want a chat-like system...where a

Yes, mastodon - and others like Gnu Social - can function in an isolated fashion. However, as others have noted, it seems you want a chat-like system...where as mastodon - and others like Gnu Social - are really meant to be social networks. You may also want to consider matrix (see matrix.org)...which is a chat-based, decentralized, open source platform...which yes can also be setup in an isolated fashion (and not phone home anywhere)...and there are also bridges between matrix and other platforms such as slack, irc, etc.; see https://matrix.org/docs/projects/try-matrix-now.html#application-services https://matrix.org/docs/projects/try-matrix-now.html#applica... I encourage you to try the main matrix.org server first using the riot.im UI/client...and if it seems like it works, you would want to proceed standing up your own matrix server within your corporate network. The reference server most people install is synapse; see https://matrix.org/docs/projects/server/synapse.html https://matrix.org/docs/projects/server/synapse.html And while it is quite performant, and somewhat the de facto thing that most people install, my guess is that the future (ref. servers) will likely be: * the Go-based Dendrite: https://github.com/matrix-org/dendrite https://github.com/matrix-org/dendrite * the Rust-based Ruma: https://github.com/ruma/ruma https://github.com/ruma/ruma I've set up my own matrix server using synapse - admittedly for my own family - and its pretty straightforward installation, and quite rock solid for being such a new platform. There are so many people building stuff for it - such as these bridges - and using it, that's it quite exciting. Again, though, matrix is for chat (e.g. irc, slack, mattermost, etc.), and mastodon/gnu social is for social network messaging. i hope that helps, cheers!!!