tailieunhanh - Establishing Connectivity

This chapter describes the basic preparation and configuration required to use the network firewall features of the Cisco PIX Firewall. After completing this chapter, you will be able to establish basic connectivity from your internal network to the public Internet or resources on your perimeter network. The basic configuration described in this chapter lets protected network users start connections, but prevents users on unprotected networks from accessing (or attacking) protected hosts. | CHA 2 r T E R Establishing Connectivity This chapter describes the basic preparation and configuration required to use the network firewall features of the Cisco PIX Firewall. After completing this chapter you will be able to establish basic connectivity from your internal network to the public Internet or resources on your perimeter network. The basic configuration described in this chapter lets protected network users start connections but prevents users on unprotected networks from accessing or attacking protected hosts. This chapter contains the following sections Setting Default Routes Configuring PIX Firewall Interfaces Configuring the PIX Firewall for Routing Establishing Outbound Connectivity with NAT and PAT Testing Connectivity Saving Your Configuration Configuration Examples Using Outside NAT Enabling Stub Multicast Routing Setting Default Routes This section describes how to set default routes on devices and hosts that communicate with the PIX Firewall. It includes the following topics Setting Default Routes for Network Routers Setting the Default Route for Network Hosts Setting Default Routes for Network Routers A router discovers and stores the paths through the network known as routes. When a router does not have a route to the destination address in a specific packet it forwards the packet using a default route to another router called the default router. Cisco PIX Firewall and VPN Configuration Guide I 78-13943-01 2-1 Chapter 2 Establishing Connectivity I Setting Default Routes Configure the default routes on your routers to forward traffic to the PIX Firewall by completing the following steps Step 1 Telnet to the router that connects to the inside interface of the PIX Firewall or connect to the router s console port. If you are using a Windows PC you can connect to the console port using the HyperTerminal program. You will need to know the username and password for the router. Step 2 Access the Cisco IOS configuration mode. Step 3 Set the default