[dnet]

In newer versions, it's disabled by default and you have to do something like this to enable in ~/.ssh/config:

    Host *
    EnableEscapeCommandline yes

[nh2]

`EnableEscapeCommandline` only controls the <Enter>~C commandline.

The reason that is disabled in current OpenSSH by default is OpenBSD `pledge` support:

https://security.stackexchange.com/questions/280793/what-att...

On my Linux,

    cat<Enter>~.

closes the connection as expected, and no ~ is shown in the terminal.