I've come here not with a problem but with a solution and I would like to know why this worked. This question is addressed to people who fully understand DNS.
For some reason (here irrelevant), our DHCP server lost it's configuration, giving IP addresses to workstations that belong to servers. This caused an IP conflict. To find out which workstation got the server's IP, we deactivated the network card on the server, flushed the DNS cache on our computers, restarted DHCP en DNS service on the server and pinged the IP. It continued to return us the server's name.
So I configured my network card on my computer to use the DNS servers from Google. I figured that way, I wouldn't receive a cached response. It worked. But I don't fully understand why. The DNS servers from Google don't know the internal IP addresses, so I guess they referred to our own DNS server but why I received the correct answer (the computer name which got the server's IP) is a mystery to me.
Can someone enlighten me?