Who’s DNS is it anyway?

So I was asked to diagnose some DNS issues a client was having recently. Not my bag, but thought I’d have a go anyway…. Two useful commands (on OSX) I found:

scutil --dns

gives you all the info about what DNS your local machine knows about. Look at anything that says “nameserver”. This is especially useful if everything’s been assigned via DHCP – the info wouldn’t appear in your GUI network preferences…. Then:

dig whatever-domain.com @10.10.10.10

queries the nameserver at the IP after the @ for it’s records on that specific domain name. Sure I knew that last bit before, but I’ll probably forget it again, so let’s write it down eh! 🙂