WHAT ARE SOME REASONABLE FILTERING RULES FOR A CISCO ROUTER?
The following example, shown in Figure 4, displays one possible configuration of a Cisco router as filtering router. It shows the implementation of a specific example policy; your policy will undoubtedly vary. In this example, a company has Class C network address of 195.55.55.0. The company network is connected to the Internet via an ISP. The company policy allows everybody access to Internet services, so all outgoing connections are accepted. All incoming connections go through the machine called mailhost. Mail and DNS are the only incoming services.
