You need to install a server in the server for this to work. That is, if you are using SSH to log in to server farms as a "user" (as opposed to a server farm admin), then you cannot just "use mosh".
When I first found out about mosh, I imagined it would work seamlessly even with servers that don’t have the mosh server installed by auto-installing itself.
If mosh could do this, I would `alias ssh=mosh` and use it all the time.
Otherwise I need to remember which servers have mosh installed, and for those that don’t I need to ssh in, apt-get mosh, disconnect, and reconnect with mosh.
I’d imagine it could either just scp a binary over to the target system (in the case of insufficient privileges) or use the system package manager to install itself.