On the Network Services > DNS > Forwarders tab you can specify so-called DNS Domain Name Service forwarders. A DNS forwarder is a Domain Name System (DNS) server on a network used to forward DNS queries for external DNS names to DNS servers outside of that network. If possible, add a DNS forwarder to your configuration. This should be a host "near" your site, preferably one provided by your Internet provider. It will be used as a "parent" cache. This will speed up DNS requests considerably. If you do not specify a forwarding name server, the root DNS servers will be queried for zone information first, taking a longer time to complete requests.
To create a DNS forwarder, proceed as follows:
Select a DNS forwarder.
Select or add a DNS forwarder. How to add a definition is explained on the Definitions & Users > Network Definitions > Network Definitions page.
Use forwarders assigned by ISP (optional): Select the Use forwarders assigned by ISP checkbox to forward DNS queries to the DNS servers of your ISP. When this box is checked, all forwarders automatically assigned by your ISP will be listed in the line below the box.
Your settings will be saved.