How does DNS security combat CnC callbacks?
A. By filtering DNS requests, it blocks all requested zone transfers.
B. By changing the DNS MX field, CnC systems cannot be reached on the outbound connection.
C. By implementing DNS security measures, CnC callbacks over any ports and protocols are blocked when the DNS queries to any bad or malicious domains are prevented.
D. Using openDNS servers, such as Google openDNS (8.8.8.8), DNS requests are filtered based on the IP reputation tables that are maintained.
E. By configuring clients to use cloud-based DNS services, CnC callbacks are originated only in the cloud.
