Changing permissions on /etc/hosts
Nothing will break (or hasn't for me whenever I resort to this on occasion) - you'll have to remember to re-do the permissions if and when the OS updates that file systematically. You'll also want to watch the permissions if you ever "repair permissions" since that file is likely recorded in a system receipt. I'd go so far as to set a launchd task to daily enforce your "custom" permissions if you feel it's worth that much work and log something to the console about the need for this "adjustment"

This is a far faster and simpler (and therefore probably better) solution to setting up your own DNS or NIS even though a trip down memory lane would be fun for a few moments:


cd /var/yp
make