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- Overview
- Firewall Review
- Static Firewall
- Stateful Firewall
- The Internet Connection Firewall
- Enabling & Disabling the ICF
- Services Options
- Adding a Service
- Programs Options
- Security Logging Options
- Setting up Security Logging
- ICMP Options
- Adjusting the ICMP Options
- Understanding the ICMP options
- Issues to clarify before enabling Internet Connection Sharing
- Enabling / Adjusting / Disabling Internet Connection Sharing
- Summary of the ICF
This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
Static Firewall
The static firewall works by examining each packet at the Network layer (Fig. 5-1) as it attempts to access a computer. By looking at the source and destination IP address and comparing them to a predefined list, the firewall will either permit or reject a packet. Although this method is effective for most purposes, it can be tedious to configure. Additionally, a static firewall can be tricked through IP spoofing. If a hacker fakes his IP address, or creates his own packets with one of the many hacker tools available on the Internet, the static firewall will think the packet is legitimate and will allow its passage.
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Figure 5-1 The OSI Reference Model