Network problems can be attributed to hardware, software, or a combination of the two. You will resolve some types of problems more often than others, while other problems may require more in-depth troubleshooting skills.
Network Connection Problems
These types of connection problems are often related to incorrect TCP/IP configurations, firewall settings, or devices that have stopped working, as shown in Figure 1.
Not being able to send or receive email is often caused by incorrect email software settings, firewall settings, and hardware connectivity issues, as shown in Figure 2.
FTP and Secure Internet Connection Problems
File transfer problems between FTP clients and servers are often caused by incorrect IP address and port settings, or security policies. Secure Internet connection problems are often related to incorrect certificate settings and ports blocked by software or hardware, as shown in Figure 3.
Problems Revealed by CLI Commands
Unexpected information reported from CLI commands is often caused by incorrect IP address settings, hardware connection issues, and firewall settings, as shown in Figure 4.