D-Link DSL-2790U User Manual page 45

Configuration
WAN Service Configuration – PPPoA
Select DNS Server Interface from available WAN interfaces OR enter static
DNS server IP addresses for the system. In ATM mode, if only a single PVC
with IPoA or static IPoE protocol is configured, Static DNS server IP addresses
must be entered.
DNS Server Interfaces can have multiple WAN interfaces served as system dns
servers but only one will be used according to the priority with the first being the
higest and the last one the lowest priority if the WAN interface is connected.
Priority order can be changed by removing all and adding them back in again.
Click the Next button to continue
WAN Service Configuration – PPPoA
This summary window allows you to confirm the settings you have just made.
Click the Apply / Save button to save your new PPP over ATM settings and
restart the Router.
WAN Service Configuration – IPoA
This window allows you to enter service description. Click the Next button to
continue.