I wonder if the Mac you are connecting too has implemented something like the hosts.deny that can be found on other *nix systems. This could be used to block all requests.
On my server I use denyhosts to populate the hosts.deny file if too many invalid connection attempts come in. Extra layer of security. -- We don't give a d@mn for the whole state of Michigan... we're from OHIO! O!H! ... I!O!
