A PPPoE client obtains DNS and NBNS name servers by including following configuration options in its IPCP Configure Request:
Primary DNS Server Address (129)
Primary NBNS Server Address (130)
Secondary DNS Server Address (131)
Secondary NBNS Server Address (132)
Note: A PPPoE DHCPv4 client does not include a Parameter Request List Option (55) in its DHCP
messages. The Domain Name Server Option (6), the NetBIOS Name Server Option (44), or
both that is returned by the DHCP server are evaluated according the authentication
origin priority to determine the DNS and NBNS name server IP address assigned to the
PPPoE session.
Mid-session changes are not supported for PPPoE DNSv4 and NBNS name server updates.