So first off, DNS is not created equal. What's going on at home, and your school is that they are not conforming to the spec. The people in charge would say it's an enhancement, and all that Redhat would have to do is licence the technology for a small fee, and they could include the enhancement in their code. The truth is that the only real enhancement is to make life difficult for those who are not using the proprietary products. You can bypass this by pointing at Google's DNS instead, which you did.
Next, you are using Selinux, which is a security feature. It's all about the contexts. The user id's have a context, which you can display with
And files have a context. You can change a files context when you edit it. That's what happened here. Then you changed it back with chcon (change context command).