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 a cache has expired based on the TTL, wherein the first set of responses include at least one response 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.