Chapter 6. Diagnosing and Correcting Firewall Issues

In the previous chapter, we discovered how to troubleshoot networking-related issues with commands such as telnet, ping, curl, netstat, tcpdump, and ip. You also learned how the TCP protocol works, as well as how domains are translated to IPs using DNS.

In this chapter, we will once again troubleshoot network-related issues; however, this time we will discover how Linux's software firewall iptables works and how to troubleshoot network issues generated by a firewall.

Diagnosing firewalls

Chapter 5, Network Troubleshooting, was all about networking and how to troubleshoot a misconfigured network. In this chapter, we are going to extend that discussion to firewalls. While troubleshooting firewalls ...

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