Several vendors such as Check Point, Juniper, Palo Alto Networks, McAfee, Fortinet and last but not least, Cisco provide hardware and software solutions to mitigate security threats. Cisco offers a specialized yet versatile security product called the Adaptive Security Appliance or ASA, which I believe is one of the best products in its class. A Cisco ASA device is a standalone hardware security appliance. Depending on model, they are quite expensive too. Currently they are beyond the scope of the CCNA Routing and Switching exam.