The following show commands are used to verify the DNS and NBNS name servers stored for a subscriber session:
show service id service-name ppp session detail
show service id service-name pppoe session detail
show service id service-name ipoe session detail
show service id service-name dhcp lease-state detail
show service id service-name dhcp6 lease-state detail
show service id service-name slaac host detail
In the following sample example only DNS and NBNS name servers output is shown:
IPv4 NBNS Primary : N/A
IPv4 NBNS Secondary : N/A
IPv4 DNS Primary : 10.1.2.1
IPv4 DNS Secondary : 10.1.2.2
IPv4 DNS Extended 1 : 10.1.4.3
IPv4 DNS Extended 2 : 10.1.4.4
IPv6 DNS Primary : 2001:db8:dddd::3:1
IPv6 DNS Secondary : 2001:db8:dddd::3:2
IPv6 DNS Extended 1 : 2001:db8:dddd::4:3
IPv6 DNS Extended 2 : 2001:db8:dddd::4:4
The primary and secondary DNS and NBNS fields are always shown. When no IP address is available, they are shown as N/A (Not Applicable). The Extended DNS fields are only present when the corresponding name server IP addresses are stored in the session state.
In exceptional cases, the DNS name servers stored for a subscriber session do not match the DNS name servers sent to the client. For example, when the DNS name servers were not requested in an Option Request Option (6) for a DHCPv6 host, the DNS name servers are stored in the subscriber session but not sent to the client.