Firewall Fundamentals

Appendix A. Firewall and Security Tools

The nature of firewalls and how they can be used to manipulate and control network traffic can make it difficult to troubleshoot network problems where firewalls are involved. Similarly, firewalls can introduce some unique and special requirements for managing and maintaining the firewall and the firewall configuration.

This appendix examines some common tools and tool usage to assist in troubleshooting, managing and maintaining firewalls.

Common Troubleshooting Tools

The most fundamental troubleshooting technique for network devices is to merely determine whether a device is reachable. Simply put, is the device up or is it down. To this end, the Packet Internet Groper (PING) utility was developed to provide ...