nd the hardware gets crashed. The attack can caused harm to the routers or switches connected with the system. Thus, it is needed to check for signature of the trusted source before upgrading the firmware. In terms of computing in SDN network, the denial of service attack is defined as (DoS attack) which is defined as when any host are getting resource temporary or permanently. This can be done by flooding a system with number of request SO that the system gets interrupted with these request and will discard the genuine or legitimate requests (Needham, 1994; Tootoonchian & Ganjali, 2010). Denial of service can be categorized into two based on type of attacks. First is classified as those attack which crashes the service whereas second attacks are those which flood the services (Lau, Rubin, Smith, et al. 2000). IP spoofing is also a kind of attack where sender IP address will be forged in order to divert the packets as in this case, the location of attacking machines cannot be easily identified. Distributed Denial of service (DDos) is a cyber attack where perpetrator uses more than one unique IP address (Nakashima, Sueyoshi, Oshima, 2010). One more type of Dos attack is advanced persistent DoS attack, this is a type of cyber attack where cyber criminals uses multiple phases to penetrate the network and obtain valuable information over period of time. APDos attack involve network layer DDos attack through to focused application layer (HTTP) floods, followed by repeated SQLi and XSS attacks (Mirkovic, Reiher, 2004; Wang, Zheng, Lou, et al., 2014). APDoS attack can be categorized as: Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Analysis of Issues in SDN Security and Solutions Advanced Reconnaissance: This include pre-attack open source intelligence (OSINT) and extensively decoyed scanning crafted to evade detection over long period. Tactical Execution: It refers to attack with a primary and secondary victims but focus is on primary Explicit Motivation: It refers to calculated