"rsync.net has no firewalls and no routers. In each location we connect to our IP provider with a dumb, unmanaged switch."
"This might seem odd, but consider: if an rsync.net storage array is a FreeBSD system running only OpenSSH, what would the firewall be ? It would be another FreeBSD system with only port 22 open. That would introduce more failure modes, fragility and complexity without gaining any security."