Evaluation of Embedded Firewall System

摘要

The performance aspect and security capabilities of the Embedded Firewall (EFW) system are studied in this thesis. EFW is a host-based, centrally controlled firewall system consisting of network interface cards and the "Policy Server" software. A network consisting of EFW clients and a Policy Server is set up in the Advanced Network Laboratory at the Naval Postgraduate School. The Smartbits packet generator is used to simulate realistic data transfer environment. The evaluation is performed centered on two main categories: performance analysis and security capability tests. TTCP program and a script written in TCL are used to perform throughput and packet loss tests respectively. The penetration and vulnerability tests are conducted in order to analyze the security capabilities of EFW. Symantec Personal Firewall is used as a representative application firewall for comparing test results. Our study shows that EFW has better performance especially in connections with high amounts of encrypted packets and more effective in preventing insider attacks. However, current implementation of EFW has some weaknesses such as not allowing sophisticated rules that application firewalls usually do. We recommend that EFW be used as one of the protection mechanisms in a system based on the defense-in-depth concept that consists of application firewalls, intrusion detection systems and gateway protocols.