LAN network troubleshooting strategy
ã€Introduction】
After we set up a small Internet cafe, in order to make the Internet cafe work properly, network maintenance becomes very important. Due to the complexity of network protocols and network equipment, many failures are not as simple as solving single-unit failures. The location and elimination of network faults requires both long-term knowledge and experience accumulation, a series of software and hardware tools, and your wisdom. Therefore, learning all the latest knowledge is what every network administrator should do.
A. Troubleshooting process
Before you start troubleshooting, it is best to prepare a pen and a notepad, and then carefully record the fault phenomenon. Pay attention to the details when observing and recording, to rule out large network faults, and the same is true for small network faults of more than a dozen computers, because sometimes it is the smallest details that make the whole problem clear.
1. Identify the fault phenomenon
As an administrator, before you troubleshoot, you must know exactly what is wrong on the network, whether you cannot share resources, or you cannot find another computer, and so on. Knowing what went wrong and being able to identify it in time is the most important step for successful troubleshooting. In order to compare with the fault phenomenon, as an administrator, you must know how the system works under normal circumstances. On the contrary, you are not good at locating problems and faults.
When identifying the fault phenomenon, the operator should be asked the following questions:
(1) When a recorded fault occurs, what process is running (that is, what operation is the operator performing on the computer).
(2) Has this process been run before?
(3) Was this process running successfully before?
(4) When was the last time this process ran successfully?
(5) What has changed since then?
With these questions to understand the problem, we can correct the problem.
2. A detailed description of the fault phenomenon
When dealing with problems reported by the operator, a detailed description of the fault phenomenon is particularly important. If based on their own words, it is sometimes difficult to draw conclusions. At this time, the administrator needs to personally operate the program that has just gone wrong, and pay attention to the error message. For example, when using a web browser to browse, no matter which website you type, it returns information such as "This page cannot be displayed." When using the ping command, no matter which IP address is pinged, timeout connection information is displayed. Error messages like these will provide a lot of valuable information to narrow down the problem. Before troubleshooting, you can follow the steps below:
(1) Collect information about fault phenomena;
(2) A detailed description of the problem and fault phenomenon;
(3) Pay attention to details;
(4) Write down all questions;
(5) Don't rush to conclusions.
3. List possible causes of errors
As a network administrator, you should consider the possible reasons why you ca n’t view the information, such as network card hardware failure, network connection failure, network device (such as hub, switch) failure, TCP / IP protocol setting improper, etc.
Note: Don't rush to conclusions, you can sort these causes according to the priority according to the possibility of error, and eliminate them one by one.
4. Narrow your search
Test all the listed possible causes of the error one by one, and do not determine whether the network in a certain area is operating normally or abnormally based on one test. In addition, don't stop at the first error that you think has been determined. You should wait until the test is finished.
In addition to testing, network administrators should also pay attention: do n’t forget to take a look at the LED indicators on the network card, Hub, Modem, and router panel. Normally, a green light indicates that the connection is normal (modem requires several green and red lights to be on), a red light indicates a connection failure, and no light indicates that there is no connection or the line is disconnected. According to the size of the data traffic, the indicator will flash fast. At the same time, don't forget to record all observation and testing methods and results.
5. Isolate errors
After some hard work, you basically know the location of the fault. For computer errors, you can start to check whether the computer's network card is installed, whether the TCP / IP protocol is installed and set up correctly, and the connection of the web browser. Whether the settings are appropriate and so on are all related to the known fault phenomena. Then the rest is troubleshooting.
Note: When opening the case, do not forget the harm of static electricity to the computer, and disassemble the computer components correctly.
6. Failure analysis
After dealing with the problem, as a network administrator, you must also understand how the failure occurred, what caused the failure, how to avoid similar failures in the future, formulate corresponding countermeasures, take necessary measures, and formulate strict Rules and regulations.
B. Failure reason
Although there are various causes of failures, in general, they are nothing more than hardware problems and software problems. To be more precise, these problems are network connectivity problems, configuration file option problems, and network protocol problems.
1. Network connectivity
Network connectivity is the first reason that should be considered after a failure. The problem of connectivity usually involves devices such as network cards, jumpers, information sockets, network cables, hubs, modems, and communication media. Among them, the damage of any device will cause the interruption of the network connection. Connectivity can usually be tested and verified using software and hardware tools. For example, when a computer cannot browse the Web, the first idea that arises in the mind of the network administrator is the problem of network connectivity. Is it right? It can be verified by testing. Can you see the online neighborhood? Can I send and receive emails? Can you ping other computers in the network? As long as one of the answers is "yes", it can be concluded that there is no problem with the connectivity of the machine to the Hub. Of course, even if you answer "No", it does not mean that there must be a problem with connectivity, but there may be a problem, because if there is a problem with the configuration of the computer's network protocol, the above phenomenon will also occur. In addition, it is also a good idea to check whether the indicator lights on the network card and the Hub interface are blinking and whether the blinking is normal.
After excluding the possibility of malfunction caused by improper configuration of the computer network protocol, you should check whether the indicators of the network card and Hub are normal and the measurement network cable is smooth.
2. Configuration files and options
Servers and computers have configuration options. Improper configuration files and configuration options can also cause network failures. Improper setting of server permissions will lead to failure of resource sharing. Improper configuration of the computer's network card will result in failure to connect. When all services in the network cannot be implemented, the Hub should be checked.
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