Fluke Networks: eliminate computer network connection faults

Network administrators often encounter network connection faults. If there are no tools, they often do not know the following troubleshooting methods. The following describes the basic steps for troubleshooting. You can learn how to use the right tools and follow six simple steps to simplify identification, isolation, and solve problems between edge switches and user computers.
Step 2: cable Inspection
First, check the cables between the computer and the network plug-in. For the 10/100 network environment, you only need a tool that can check the open, short circuit, and wiring. For Gigabit Ethernet, check for crosstalk and impedance faults in the cables. We recommend that you use a cable identification tester to test string and impedance faults in a real-time network.
Step 2: confirm to connect to the vswitch
Connect a portable network tool instead of a faulty computer to an office line and check whether a link can be established. If the port is disabled by the Administrator, the tool cannot be connected. Then, check the port configuration to ensure that the port is available and configured according to the correct VLAN. Tools that support 10/100/Gig connections should be used for optimal results. However, the 10/100 Connection Tool usually works.
Step 2: Apply for a DHCP address
Once a link is established, you can use the tool to apply for a DHCP address from the server. Ensure that the allocated address matches the corresponding subnet; check the subnet mask; and confirm the default gateway and DNS server address. If the tool fails to get a response from the server, it should be able to detect the corresponding subnet by analyzing the broadcast traffic. Check the port of the switch that the tool is connected to and confirm the subnet configuration through the Cisco Discovery Protocol (CDP) report obtained from the switch.

Figure 1: ES2 network connection is used to check whether the network can be accessed normally and the IP address can be obtained smoothly.

Step 2: Ping the devices on the network
Once the DHCP address is obtained, you can use the tool to ping a device outside the LAN. This confirms whether the specified configuration of the DHCP server is correct and whether the network traffic is routed correctly. At this time, the network connection has been tested, so the computer can re-connect to the network. For persistent network connection problems, it is best to use an online connection tool between the computer and the Network for additional diagnosis.
Step 2: Check speed/Duplex Mode settings
Some link performance faults, such as Duplex Mode Mismatch, speed mismatch, and static IP addresses, can only be detected online. Therefore, we strongly recommend that you use tools with online detection functions. Connect tools online between computers and networks. Confirm that the speed setting and duplex mode setting of the port of the connected switch are consistent with those of the corresponding computer. If the duplex mode does not match, check whether the computer and switch ports have been set as automatic protocols.

Figure 2: The NetTool network multimeter is used to test the connection status of network devices at both ends online to obtain the level, transmission line pair, duplex, and adaptive rate.

Step 2: Network Traffic Monitoring
Use online tools to check whether the computer has successfully applied to the DHCP server and received the address. This tool should be able to establish independent connections with the network and then establish connections with the computer. Then, use a computer to connect to the email server or application server, and monitor network traffic through tools. Find too many broadcasts, conflicts, or errors. Once all these parameters are verified, the link between the computer and the network can be canceled. If the fault persists, more precise network diagnostic tools may be required.