The "Domain Name System" is a service translating domain names, i.e. the names of computers and networks, to IP addresses and vice versa. Using DNS, additional information can be published, e.g. about the e-mail receving and sending server for a domain.
The AIP runs a system consisting of several DNS servers serving various zones. The master for all AIP-zones is the primary name server (pns.aip.de). You should not query this server directly, because it will not answer queries for addresses outside the AIP (non-recursive operation).
Due to security considerations, DNS servers outside the AIP are not accessible for normal workstations or servers inside the AIP network. All AIP-internal computers should use the two DNS forwarders of the institute. They will answer all queries and at the same time check DNSSEC zones:
The settings for a Linux system might look like this:
If your computer is configured for DHCP it will be assigned a suitable DNS server or forwarder by the DHCP server. Other DNS servers outside the AIP are normally not reachable. Therefore you should not change this configuration