[johnklos]

"Right now our provider is getting DdoS'ed, so my employer is not reachable by mail, web etc."

"our" here might suggest that your provider is also your employer's provider, and that your employer is not reachable in general by anyone by mail, web, et cetera. But reading the rest of your message makes me think that perhaps you're saying that your personal provider is being attacked, not your employer's, and therefore you can't reach your employer's mail, web, et cetera. Is that the case?

Is the attack just taking out your provider's DNS servers? If so, then just run your own recursive resolver. It's literally as easy as setting up BIND on any machine on your network with a default configuration file that does the barest minimum. Clients on the same subnet will be able to query it without problems.

There's no reason, nor advantage, to running anything using your provider's DNS servers when you have your own, particularly when their DNS servers can be taken down so easily.