It's client-side, so works even if the remote system is totally hung and did not clearly disconnect.
For example, running `systemctl suspend` will not terminate active SSH connections before putting the destination machine into a sleep state, and thus Ctrl+C (which isn't processed by SSH) will do nothing until the remote host is woken up by some mechanism.
For example, running `systemctl suspend` will not terminate active SSH connections before putting the destination machine into a sleep state, and thus Ctrl+C (which isn't processed by SSH) will do nothing until the remote host is woken up by some mechanism.