Enable Remote Login to Start SSH Server in Mac OS X

refs:

http://osxdaily.com/2011/09/30/remote-login-ssh-server-mac-os-x/

1. Open System Preferences from the  Apple menu, and click on the “Sharing” preference panel
2. Select the checkbox next to “Remote Login” to enable it, like the screenshot indicates

Clicking the checkbox will instantly start the various remote login servers, including sftp and ssh.

If you want to limit incoming SSH access to certain users, you can do so in the same preference panel by ticking “Only these users” and then manually adding them by clicking on the + icon. This brings up a list of Users & Groups on the Mac that you can select from. Think of this as an extra security step, although SSH by default is quite secure as is due to the nature of the protocol.