Comment 16 for bug 471498

For the network manager side of this bug. According to Mario

"If you replace /etc/hosts with a zero length file (as some editors may do in the process of saving), there is a chance you'll hit this, but it's still not guaranteed. You don't need to duplicate it to fix it. You just need to modify NM code to write out a proper /etc/hosts."

So the issue with Network Manger is it is not filling out /etc/hosts with proper content if it sees that it has no content.