1. A method for managing traffic-overload in a DNS server during a network overload, the method comprising: monitoring traffic associated with the DNS server, wherein the traffic includes at least one of a plurality of requests received by the DNS server and a plurality of responses transmitted by the DNS server; identifying an occurrence of an event to trigger a rescue mode, wherein the rescue mode enables implementation of at least one policy for handling of the traffic associated with the DNS server; and implementing the at least one policy upon occurrence of the event, for handling the traffic, wherein the at least one policy comprises: segregating the plurality of requests into a first set of requests, a second set of requests, and a third set of requests based on availability of responses in a cache corresponding to the plurality of requests, and a Time to Live (TTL) associated with the responses, wherein the cache is associated with the DNS server; processing, without communicating with a backend server, the first set of requests from amongst the plurality of requests for which a first set of responses stored in the cache has expired based on the TTL, wherein the first set of responses include at least one response for each request from amongst the first set of requests; and transmitting the first set of responses to a plurality of client devices, wherein the first set of responses includes expired data.