Firewall is one of the most popular security software installed on millions of Internet connected computers worldwide. Today’s PCs need the protection provided by a firewall to ensure the safety of both personal data, in-bound and outbound traffic. Having a firewall, benefits the user and the PC by shielding them from the attacks of malicious users, would be the general thinking of a common PC user. Are these Personal Firewalls, which are provided by the most popular Antivirus companies to protect your system, safe? This is the question that we are trying to answer in this paper by evaluating the effec-tiveness of these personal firewalls. We know that the Firewall plays a vital role in defending against DDoS attacks. Sometimes they will cause some overhead while they are defending against the DDoS attacks.