Please answer Q.B4 In relation to Cyber security

Q.B4 DNS Cache Poisoning The domain name system (DNS) is responsible for providing access to the IP addresses that specific domain names are mapped to. It accomplishes this using a distributed system in which DNS servers that do not know the mapping for a given domain name refer the system sending the query to another DNS server that may know instead. DNS servers let each other know what domain name ranges they can handle and each caches this information to use for future requests they cannot themselves answer. a) Explain how an attacker can trick a legitimate DNS server into referring systems querying it to the attacker's own DNS server. (10 marks) b) Evaluate the seriousness of such an attack against the DNS servers belonging to an internet service provider and suggest what the attackers might gain by it. (10 marks) c) Given that DNS is a fundamental part of the infrastructure of the internet, evaluate the seriousness of both this vulnerability and the effectiveness of the DNS security extensions (DNSSEC) that have been developed to address it. (10 marks) (30 marks in total)