Linux Troubleshooting: Troubleshoot Networks

Here are the initial instructions and explanation of the lab environment. Read this while your environment is busy creating itself from nothing. Yes, this violates physics; we know. How fun!

To start the lab, you will gain hands-on experience in understanding how to check the network details of a server and test the connectivity between servers using the ping command.

Now, you will learn how to check the statistics of your NIC (Network Interface Card) and view raw data. By doing so, you can troubleshoot any issues that may arise from a malfunctioning NIC or port. These issues can lead to packet drops, which in turn can cause packet retransmissions, and have a negative impact on network performance.

The goal of this challenge is to comprehend the purpose and functionality of the /etc/nsswitch.conf file. Additionally, you will examine how the system utilizes the nss configuration file to query the server. Moreover, you will acquire practical knowledge of various commands such as resolvectl, dig, and getent. These commands are employed for querying and resolving the Domain Name System (DNS).

You will test network access by pinging the default gateway, and will troubleshoot subnet-related issues. You will also learn various shortened addresses to use with ping.

In order to complete this lab, you will be taught how to configure the server's firewall. Additionally, you will utilize the nmap command to scan the ports on a remote server. Your objective is to permit a specific port to pass through the firewall from one server, and subsequently confirm its accessibility from another server.