When searching for a specific name, the DNS server searches using all of the information available to it:
- First the DNS server checks whether access to this name is prohibited by the filter list. If so, an error message informs the requesting computer that it is not permitted access to this name.
- The server then searches its own static DNS table for entries with the corresponding name.
- If the DNS table has no entry for this name, the dynamic DHCP table is searched. Use of the DHCP information can be disabled if necessary.
- Finally, the DNS server checks whether the request should be forwarded to another DNS server via a WAN interface (special DNS forwarding via the DNS destination table).
If the name is still not found after searching all of the available information, the DNS server forwards the request to a further DNS server (e.g. at the Internet provider) using the general DNS forwarding mechanism. Otherwise it will send an error message to the requesting computer.
