1. A method for separation of traffic processing in a software defined network (SDN), wherein the method is performed by a central controller of the SDN, comprising: allocating a first group of computing resources of a computing farm to a trusted zone and a second group of computing resources to an un-trusted zone; assigning the computing resources in the first group with a first address and the computing resources in the second group with a second address, wherein only the second address is advertised; triggering a zoning mode in the computing frame to mitigate a potential cyber-attack; causing at least one network element in the SDN to divert an incoming traffic to the first group and the second group of computing resources based on a plurality of zoning rules implemented by the at least one network element, wherein the plurality of zoning rules are determined by the central controller and determine that the traffic from a trusted client is directed to the first group of computing resources and the traffic from an un-trusted client is directed to the second group of computing resources, thereby providing guaranteed SLA to trusted clients.