Q: Several of our classmates have set up a shared network in the dormitory, altogether is a notebook and two desktops, three machines surf together. Dial-up Internet access via a broadband router the use of Soho-level multi-functional broadband router, with wireless capabilities, usually we are three people sharing the internet to play games and browsing the web, but we recently found that the dormitory network is too unstable, can be said to the point of intolerable, peacetime network use process often drop line.
After repeated testing and recording of the fault information, we found a failure rule, that is basically half an hour automatically dropped once, but every time after the line after waiting for a while to return to normal, although you can continue to use the network, but we know that we play the game off the line once, The characters in the game is likely to be in the game and be blamed to kill or be the player PK, so want to ask what is the cause of this problem, hope the Master can guide twos, help us introduce this problem, let our network intact operation.
A : from this netizen's narration we can understand that the dormitory network structure is relatively simple, just through a low-end broadband wireless router and three machines share surfing. The key to the problem is to drop the line once in half an hour, and then recover immediately after the line is dropped. So exactly what caused the problem?
According to the author's experience network drop line can be divided into two categories, one is the equipment itself, such as the device itself hardware problems caused by network instability and interruption, or the hardware itself interface quality caused by network connectivity is not smooth; the other is software problems, such as parameter setting failure or virus caused. So our analysis of this instance problem should also proceed from these two aspects.
(1) Hardware problem:
Generally speaking, broadband router hardware failure probability is relatively low, and because this example mentioned the disconnection after a minute again normal. So the device hardware problem is not likely, there may be a line problem, and the telecommunications department to inquire about the use of ADSL dial-up telephone line is a problem, or because the dormitory telephone has an extension, resulting in a string of interference and off line. At this point can remove the extension or through a tool called the divider to achieve frequency division to reduce interference signals.
(2) Software problems:
The software problem is either a parameter setting error or a client computer virus causing the failure. Both of these situations are possible from the clues provided by the reader. Here we turn to the different problems of the examination and resolution.
If the client computer virus, especially such as the ARP spoofing type of worm caused, then when the network accumulated enough virus packets will generate a lot of traffic impact on the broadband router port, when the traffic is too large the router port will appear self-protection, that is, automatically shut down the port to disable it, To discard all virus packets. At this point, the client computer will appear out of line can not connect to the external network phenomenon; And when the broadband router self-protection shutdown port after the virus packets are discarded, so a short time (less than a minute) the port will automatically return to normal, which is why the reader encountered the actual disconnection problem after a minute or so back to normal reason.
When the fault is caused by ARP spoofing virus, we should first of all client computer operation system installation system patches, to make up for various vulnerabilities, the next to install antivirus software update virus to kill worms, if necessary, can also be combined with arp-d clear ARP cache information to restore normal network. Only after the complete removal of the virus can let the network back to normal, solve the above mentioned automatic line drop problem. Of course, for some of the more powerful ARP virus, we can only use tools to solve, for example, install an ARP firewall in this machine or the binding Mac function of the router to restrict the virus attack and spread, these are very effective prevention methods, in the author's actual use and maintenance process of the effect is remarkable.
Of course, if the problem is not caused by the virus, then most likely is the broadband router software parameter setting problem, we can go to the broadband router management interface. One by one set the information for each parameter, especially the dialing setting at the "Network parameter->wan port setting" To see if he is set to "on-demand connection, automatic connection when there is access, automatic disconnection waiting time x minutes". If this is the case, then someone in the intranet to access the external Internet, broadband routers will dial the Internet, and when the network needs in X minutes without network access will be automatically disconnected. We can modify it to "automatic connection, in the boot and disconnect automatically after the disconnection" to solve the problem, remove the automatic disconnection network phenomenon.
Improper software settings may also appear in the reader's narrative, as mentioned above, when the WAN port dialing parameter settings error, when the network in five minutes without internet access when the broadband router automatically cut off the external network dial-up connection, then someone will find that no Internet access, And the broadband router will be in the next minute in accordance with the "on-demand" mode, in the case of someone with access to the need to dial again to connect the ADSL line, resulting in a minute after the network back to normal phenomenon.
In addition, the routers in the software settings for the allocation of IP addresses of different clients also arouse our attention, for example, to two computers the same IP address, they will conflict between, and caused one of them can not access the Internet. Reasonable allocation of DHCP automatically allocate network address function, and set each client through DHCP rather than manually set the fixed IP address parameters such as the method to obtain network information, so as to completely solve this problem.
In short, in the actual network troubleshooting process, we can according to the hardware + software combination of the route to judge the fault, especially the software, from settings and viruses to solve the actual network problem is the begotten of home network maintenance.