Applications
Configure Firewall
The router provides Firewall security for restricting access between any two networks connected through the router. Firewalls are set up on a per connection basis for the LAN and remote sites. The direction of filtering is from the perspective of the router; incoming traffic is from the network in question to the router, outgoing is from the router to the network. The direction of filtering may be set to incoming, outgoing, both or none. Once the direction of filtering for a connection has been set, holes may be created in the firewall to allow specified traffic through. Normally, the LAN firewall is used for restricting intranet traffic (connections within the corporate network) and remote site firewalls are used to limit access from less trusted sources, such as the Internet or
Main FTP server: 195.100.1.12
Main Web server: 195.100.1.20
Corporate Head
Office Network
195.100.1.0 
Branch Office 
Network 
195.100.2.0
Router with firewall enabled.
Internet 
Any other network any IP address
Figure 2-10 Sample Firewall Application
The above diagram shows a corporate head office network, which is connected, to the Internet with an router. There is also a branch office at a remote site connected with a Digital Leased link. The administrator at the corporate head office wishes to set up an IP firewall to allow everyone on the Internet to have access to the corporate FTP and Web servers and nothing else. The administrator
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