tailieunhanh - Troubleshooting Example

This through a simple example of troubleshooting a firewall configuration. Troubleshooting starts with the basic connectivity troubleshooting and escalates upward to more complex issues until the specific problem is identified | Troubleshooting Example This section walks through a simple example of troubleshooting a firewall configuration. Troubleshooting starts with the basic connectivity troubleshooting and escalates upward to more complex issues until the specific problem is identified. As mentioned previously the first step is to verify the problem that is being reported. Consider for example the problem shown in Figure 13-3. The web client behind the firewall is attempting to reach a website across the Internet. For the purposes of this example we use the site http . Figure 13-3. Troubleshooting Example Topology Figure 13-4 shows that the connection has failed. This failure could be for a variety of reasons but suffices as a simple example of troubleshooting the firewall. Figure 13-4. Failed Connection to Website View full size image One of the first steps to take is to test the connectivity. Doing so involves verifying that the firewall is up and running as well as verifying that the Internet connection is working. To verify that the firewall is operational from a hardware perspective requires a physical examination of the firewall device. The firewall power light should be on and both inside and outside interface indicators should be on. These indicators vary depending on the specific brand of firewall. On the PIX they are found on the interface ports themselves as shown by the two arrows in Figure 13-5. Figure 13-5. PIX Interface Indicators View full size image If the firewall is up and functional the next step is to connect to the firewall and verify that the firewall software has not crashed. You can do so either using the firewall s web interface or by using the command-line interface. Figure 13-6 shows a connection into a firewall and verification that the software is up and running. Figure 13-6. Verifying Firewall Functioning View full size image