To set the window title in tmux or screen to the hostname you are connecting by ssh, add this to your ~/.bashrc:
settitle() {
printf "\033k$1\033\\"
}
ssh() {
local sshargs=("$@")
local do_settitle=1
tty -s || local do_settitle=0
if [ "${TERM:0:6}" != "screen" ]; then
local do_settitle=0
fi
if [ $do_settitle -eq 1 ]; then
if [ "$1" == "-l" ]; then
shift 2
fi
settitle "$*"
fi
command ssh "${sshargs[@]}"
if [ $do_settitle -eq 1 ]; then
settitle "bash"
fi
}