Which option describes how DNS snooping is used on the Cisco ASR 5000?
A. DNS snooping allows the Cisco ASR 5000 to snoop DNS query packets and compare against known DNS responses. If a match is found, the Cisco ASR 5000 replies to the query itself instead of forwarding the query to the destination DNS server.
B. DNS snooping allows the Cisco ASR 5000 to detect if a DNS response sent back to a subscriber is valid. If the response is invalid, the Cisco ASR 5000 drops the packet.
C. DNS snooping allows the Cisco ASR 5000 to enable set of dynamic IP rules to be installed based on the response to DNS queries sent by a subscriber that matches a configured domain rule definition. Dynamic IP rules are created for these IP entries within the same rule that has the domain name, which applies the same charging action to these dynamic rules.
D. DNS snooping allows the Cisco ASR 5000 to enable set of dynamic domain rules to be installed based on the response to DNS queries sent by a subscriber that matches a configured domain rule definition. Dynamic domain rules are created for the DNS responses within the same rule that has the domain name, which applies the same charging action to these dynamic rules.
