Lan network troubleshooting Policy

After we set up a small Internet cafe, network maintenance is very important to make it work properly. Due to the complexity of network protocols and network equipment, it is not as easy to solve many faults as solving single-host faults. The identification and elimination of network faults require both long-term knowledge and experience, a series of software and hardware tools, and your wisdom. Therefore, every network administrator should learn more about the latest knowledge.
A. troubleshooting Process
Before you start troubleshooting, You 'd better prepare a pen and a notebook, and record the fault carefully. Pay attention to the details when observing and recording, and eliminate large network faults. Generally, the small network faults of more than a dozen computers are also the case, because sometimes the smallest details make the entire problem clearer.
1. Fault Identification
As an administrator, you must know exactly what went wrong on the network before troubleshooting, whether to share resources or not find another computer. Identifying the problem and identifying it in a timely manner is the most important step for successful troubleshooting. To compare with the fault phenomenon, as an administrator, you must know how the system works normally. On the contrary, you cannot locate the problem or fault.
When identifying faults, ask the operator the following questions:
What processes are running when a recorded fault occurs (that is, what operations are being performed by the operator on the computer ).
Has this process been run before?
Was the previous process running successfully?
When is the last successful running of this process?
Since then, what changes have taken place?
With these questions to understand the problem, you can remedy the problem and eliminate the fault.
2. Describe the fault symptom in detail
When handling issues reported by the operator, a detailed description of the fault phenomenon is particularly important. If you only rely on one of them, it is sometimes difficult to draw conclusions, then the administrator needs to operate the program that just went wrong and pay attention to the error information. For example, when you use a Web browser to browse, no matter which website you type, information such as "this page cannot be displayed" is returned. When you run the ping command, no matter which IP address you ping, the timeout connection information is displayed. Such error messages provide valuable information for narrowing down the problem scope. Before troubleshooting, follow these steps:
Collect fault information;
Describes problems and fault phenomena in detail;
Pay attention to details;
Write down all the problems;
Do not rush to conclusions.
3. list possible causes of errors
As a network administrator, you should consider the possible causes of inability to view information, such as NIC hardware faults, network connection faults, and network equipment (such as hubs and switches) faults, improper TCP/IP protocol settings, etc.
Note: Do not rush to draw conclusions. You can sort the causes by priority based on the possibility of errors and exclude them one by one.
4. Narrow the search scope
Test the causes of all listed errors one by one. Do not use one test to determine whether the network in a region is normal or abnormal. In addition, do not stop on the first error that you think has been identified. It should be done until the test is complete.
In addition to testing, the network administrator should also note: do not forget to take a look at the LED lights on the NIC, Hub, Modem, and router panel. In general, the green light indicates that the connection is normal (several green lights and red lights are required for the Modem), the red light indicates that the connection is faulty, and the light indicates that there is no connection or the line is disconnected. Depending on the data traffic, the indicator will flash slowly. At the same time, do not forget to record all the means and results of observation and testing.
5. Isolation Error
After some hard work, you basically know the faulty part, you can start to check whether the computer Nic is installed, whether the TCP/IP protocol is installed and set correctly, and whether the Web browser connection is properly configured. The rest is troubleshooting.
Note: Do not forget the damage caused by static electricity to the computer when the chassis is opened. Remove computer components correctly.
6. Fault Analysis
After the problem is solved, as a network administrator, you must also understand how the fault occurred, why it led to the fault, and how to avoid similar faults in the future, and formulate corresponding countermeasures, take necessary measures to formulate strict rules and regulations.
B. Fault Causes
Although there are a variety of Fault Causes, hardware and software problems are generally more accurate. These problems are network connectivity problems, configuration file options, and network protocol problems.
1. Network Connectivity
Network connectivity is the first reason to consider when a fault occurs. Connectivity problems usually involve Nic, jumper, information socket, network cable, Hub, Modem and other devices and communication media. If any device is damaged, the network connection may be interrupted. Connectivity can usually be tested and verified using software and hardware tools. For example, when a computer cannot browse the Web, the first thought in the network administrator's mind is network connectivity. Is it true? It can be verified by testing. Can I see my network neighbors? Can I send and receive emails? Can I ping other computers in the network? If one of the answers is "yes", it can be determined that the connectivity between the local machine and the Hub is correct. Of course, even if "No" is answered, it does not mean that there must be a problem with connectivity, but may be a problem, if a problem occurs in the computer's network protocol configuration, the above problem may occur. In addition, it is not a bad idea to check whether the indicator on the nic and Hub interface is blinking and whether the flash is normal.
If the fault is caused by improper Computer Network Protocol configuration, check whether the nic and Hub indicators are normal and whether the network cables are smooth.
2. configuration files and options
Configuration options are available for servers and computers. Improper configuration files and options can also cause network faults. If the server permission is improperly set, resources cannot be shared. Improper computer Nic configuration may lead to connection failures. When all services in the network cannot be implemented, check the Hub.(