I had no idea Mosh did not support tmux control mode. I was hoping to eventually use Mosh more, but not any more.
Glad to see Eternal Terminal works with FreeBSD too.
Just installed it on my server. Package doesn't include any rc.d service file though. And I am fairly certain that unlike mosh, the Eternal Terminal etserver needs to run as a service, seeing as that is what they do on Linux and on macOS.
I'm gonna open an issue about it on their issue tracker.
Issue: https://github.com/MisterTea/EternalTerminal/issues/253
PR: https://github.com/MisterTea/EternalTerminal/pull/255
Note that the version in FreeBSD ports was a bit out of date and they changed the command-line flags between then and now so I built the most recent version from source and had to make a small change in CMakeLists.txt in order to be able to build it, for which I submitted a separate PR.
CMakeLists.txt PR: https://github.com/MisterTea/EternalTerminal/pull/254
If these two PRs are accepted and a new version of Eternal Terminal is released with these changes included then I can ask the FreeBSD package maintainers to update the port and for that rc.d service file to be included in the FreeBSD port and package.