~/.ssh/config doesn't work anymore on Yosemite

I'm trying to create my ~/.ssh/config file for simplify my work life on the server connection.

In Mavericks all worked properly with file like this:

Host test-host-name
    HostName 123.123.123.345
    User root

# IP is specifically incorrect for secure reason

The same configuration now doesn't work on Yosemite.

Do someone know if is something changed in Yosemite and now I need to do something to make it work?