Introduction to Firewall Technologies

Objectives Upon completion of this course, you will be able to: Understand basic concepts of network security Master mandatory firewall technologies

3Com Confidential. 3 Contents Network Security Firewall Technologies

Network Security Overview Network security is a practical issue on the Internet Network security is a comprehensive technology Network security has two meanings: –Guarantee security of the internal LAN (away from illegal invasion) –Protect security of data exchange with the external network Perfection and update of the network security technology

Coverage of Network Security Coverage of network security –Prevent physical lines of the network from being easily attacked –Effectively identify legal and illegal users –Implement effective access control –Guarantee concealment of the internal network –Offer an effective anti-forgery means to focus on major data –Provide security management for network equipment and network topology –Provide virus protection –Improve security protection consciousness Category of network security devices

3Com Confidential. 6 Contents Network Security Firewall Technologies

Mandatory Firewall Technologies As for different kinds of potential security hazards on the network, the firewall must have the following security features: –Network isolation & access control –Attack defending –Network Address Translation (NAT) –Application Specific Packet Filter (ASPF) –ID authentication –Content filter –Security management

Network Isolation & Access Control Firewall Switch Trusted Zone Untrusted Zone DMZ Trusted Zone -> DMZ, accessing POP3 and SMTP services DMZ -> Trusted Zone, accessing no services Untrusted Zone -> DMZ, accessing POP3 and SMTP services DMZ -> Untrusted Zone, accessing all services Trusted Zone and Untrusted Zone cannot access each other Server

Attack Defending Firewall Trusted Zone Untrusted Zone DoS attack Hacker Normal user Prevent

Network Address Translation (NAT) Firewall Web Server / → ←

Application Specific Packet Filter (ASPF) Dynamically create and delete filter rules Monitor packets in the communication process

ID Authentication Firewall Access the Internet User name and password? Input the user name and password Authentication success Normal Internet access

Content Filter Normal website Harmful website Internet Harmful contents Healthy contents Filter harmful websites Remove malicious webpage contents

Security Management Internet Log buffer Monitoring terminal Console Log host SecPath

Summary Basic concepts of network security Mandatory firewall technologies

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