Frequently Asked Questions
LAN troubleshooting LAN’s biggest advantage is resource sharing, but in practical use often encounter this problem: the other side obviously has shared a variety of resources to the LAN can not access them. As the result that Many species of the possibility of failure, usually novices find difficult in a short time the fault lies, so in this instance the form of LAN failure to conduct a comprehensive analysis.
1. sheep lice out of sheep – no card failure phenomenon】 【obedient
a PCI card, in Windows, can automatically install the drivers, and have properly configured network protocols and associated parameters, but in general there network when used under good behavior, after the replacement of other cards This problem still exists; and piece of card in the other computer as usual.
】 【analyze and solve network card drivers first to ensure that is correct, the best driver that is included using the card, or in accordance with the network card model to drive House (http://www.mydrivers.com) Download the appropriate driver. If there is no driver, you can chip based network card to the Lord of the manufacturers to try to install.
the network card driver installation has finished, enter \the card, but there is a conflict, and other hardware. At this point there are two solutions: First, delete or temporarily disable network card conflict with another device (such as sound cards), and then try restarting problems can be resolved if they can solve, then reinstall sound card driver or change the sound card number so that the two will not interrupt the conflict; Another way is to remove the network card driver and then reinstall, if necessary, adjust the space occupied by the interrupt number card, up until the conflict no longer occurs.
If there is a resource conflict, in the \Some cards use the interrupt address is \\Graphic conflict can BIOS will \there is a yellow exclamation mark, is obviously driven installation is not successful, but the correct driver installed N times does not work, you guessed how? later found to be loose network card.
2.
【bad environment fault phenomena 】 LAN computers to connect, share both normal copies of a few megabytes in the network, or dozens of megabytes of files are also normal, but when copying hundreds of megabytes file, one on a \prompt, and then could not find \copy data require frequent data access, which have a relatively stable transmission environment, if there is interference in the network line will make this stable environment has been destroyed, a network failure occurs. However, hubs, routers and switches and other network equipment to external interference is not very sensitive to disturbance may be the largest in the network card or cable link.
for the card, the more compact structure, if the chassis will be installed next to the graphics card, sound card and other card in the slot, these cards could lead to mutual interference between the electromagnetic wave, resulting in large file copy error occurred. workaround is to turn off the computer after unplugging the card, re-inserted in a card from or the distant sound card slot.
for the network cable is recommended you use shielded cable, this is because they are usually interference shielding layer of protection to prevent external electromagnetic interference, currently on the market five five wire cable or over shielded cables are basically. In addition, the suggestion is not in the computer, network cable and hubs and other network equipment placed near the TV sets, stereos and other appliances.
3.Ping you Ping to 10 million times – barrier
fault phenomena】 【LAN with two computers can connect to other computers and use the other computer resources, but the two computers can not Ping Tung.
【Analysis and Resolution 】 As can connect to other computers, which shows the network connections and network protocols have been no problems, so the main property is set from the software side to consider. As Ping uses the ICMP protocol, so that most failures occurred in the other computer Install a firewall software, and when the shield of the ICMP protocol. so need to check the computer’s firewall software settings to see if the shield of the ICMP protocol.
In addition, Windows XP, activating the system with the firewall, it will automatically shielding some common network capabilities. such as a computer in the network using ping command to detect the network connection status, it will see \introduction of Huixianqingqiu \, the only view that part of the computer can not view some of the computer to the LAN, even your own computer, how is this going on here?
】 【analysis and solve the premise of flow in the LAN, either can not view this machine or other computers on the network are due to the computer can not view not installed properly due to file and print sharing services.
installation file and print services in Control Panel, double-click \in the pop-up window, click the \; network \.
Also, if the LAN computer in a workgroup setting error may not be directly in a view of a working group to it. such as most computers working group is set to \group is set to \network \use \yellow, indicating that line barrier (the state of different types of card shows a different light, usually to observe). If the show is bad, use the survey line tester cable, also check card is a problem. Generally cable barrier The probability is high, less likely bad card. If you ruled out hardware failure, then proceed to Step 2.
binary Step 2: Determine whether the problem
not Internet-based machines are generally caused by local failure, individual time may be due to the campus network switching equipment or a proxy server problems. to determine whether the machine in question is the easy way to ask whether the Internet network management and other colleagues. Should the judge-based machine, please proceed to Step 3.
binary Step 3: Identify the problem or the card is the security setting set to issue
implementation of the \<10ms ttl = 128 \, if a Windows 98 system, you can reinstall IE; if the Windows 2000 system, should also look at the safety-related IP settings to determine whether there is port address shielding. If the Internet, but many sites get in, or E-mail can not log in, you must have IE be modified, re-install IE solved. If no response packet is sent, then the problem should be the network card in the machine-related settings. Should the settings identified as card-related issues, go to step 4 .
binary Step 4: Determine the network card driver installation problem or IP-related property is set incorrectly
implementation of \China to see themselves, network card drivers usually no problem, the problem should be focused on IP property settings on the network card. If the LAN computer is set to \DHCP for WINS resolution \DNS, gateway and WINS settings on the relevant. The content and the unit’s LAN configuration, please flexibility. If the ping 127.0.0.1 does not respond, then the network card drivers are installed there must be problems. re-install, and configure accordingly.
There are very special case, Ke Yi Yong ping command ping Tong Zi Ji, My Network Places Quekan not see any computer, check the TCP / IP of the Pei Zhi Du no problem, but can not Shang Wang Jiu Shi. This issue Duoshu yes the computer Bingduyinqi , the anti-virus and re-install the network card drivers can solve the problem. I’ve had several cases of this phenomenon have been using this method have been successfully resolved.
specific configurations for different local area network is different, related issues, please flexibility.
Windows XP network problems easily check
Source: China Computer Education
Editor: ycx
[03-10-17 10:21] on: Swiss Air
when the network fails, Your first thought is not in the command prompt to input a number of related commands, such as ping to diagnose? In fact, ah, Windows XP can use the \> Step 1 Click \the window, select \Select \3 After ten seconds of waiting, a variety of tests conducted to collect detailed information on the diagnostic report is complete. including whether your system has network connectivity, and network-related programs and services is running, and on your computer’s basic information.
how, you find the right network failure
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calm loop caused by broadcast storms
of: Huang Ying
author is a network management . Recently, we have to transform the local area network, network cable all the re-taking the original 70 points throughout the network, all joint topology, there are more than 30 users, just add a switch that can be had. current network structure is this: the entire network all use the star topology, the center room is equipped with a TCL of the three switches, servers mainly provide FTP, file services, Web and many other services. TCL switch used on each floor, all with with VLAN technology, each terminal by Fast Avaya network cable access network. When the network has just started all pretty good, but the network has often been dropped recently, and sometimes even strike altogether. leading to I three days to solve the problem, to and he is not on bye. Woo, woo, woo hh Fortunately, hard work pays off, three day and night to brood over after I finally buttoned the problem. Now, my colleagues have called me a yellow workers, wages will probably rise substantially, Ha ha ha hh the following Returning to the subject:
saying that one day a certain period, there are N users reflect the network connection through the time when off-line neighbors and sometimes can not be exchanged visits, as users spread across multiple floors fault, not the point of failure concentrated, were particularly bad. At first I thought the information overload switch port plug, the switch, the server restarted N times, or not do. was, we quickly begin to discuss from the software, start the server anti-virus, and then Turn off all switches, anti-virus on each machine, but the fault still exists. In the Ping network part of the server or computer, still packet loss, network intermittent.
My God, I’m really mad! day at home, carefully recalled that day failure, found that anti-virus and when I switch off the individual, the network returned to normal, and I once again plugged in to the time, they once again broken. think of here, there have been little prospect of a solution. The next day at work, I broke all the switches, then one by one to plug in, until you find the problem one. After careful observation, finally found the problem. the original was done when the network core switch and the sub-switch are left between the two cascade lines, usually inserted only one other alternative. The two switches are in the plug, and when the user switches to another user to send messages, data packets will be along the other root backup line, loop through the core switch to send packets. When large amount of information, when the core switch will be a waste of resources, resulting in speeds up to break down.
The failure was mainly due to network There exist loop, resulting in each frame is repeated in the broadcast network, causing the broadcast storm. To remove such a network loop connecting a network broadcast storm brought STP protocol can be used, we can access Cisco Systems and other related books, in This is not much to say. In addition, since we are doing the larger network, we must build more files, including network wiring diagram, IP and MAC corresponds to the table and so on, and on the wire sets of digital control. The failure have been confirmed because a new colleague carelessness.
——< br> IP and MAC binding problem
Q: My computer had a fixed IP address using the public network. In order to avoid unauthorized personnel, use \Strangely enough, after the abolition of binding in the other computer still can not use the IP address, but only in my own computer. need to explain that my computer is not a proxy server.
A: Although In the TCP / IP network, the computer often need to set IP address to communication, however, is not in fact the communication between computers via IP address, but the help of NIC’s MAC address. IP address is only used to query For Newsletter The purpose of the computer’s MAC address.
ARP protocol is used to each other’s computers, network equipment, notify your IP address corresponding to the MAC. in the computer’s ARP cache contains one or more tables for storing the IP address and The Ethernet MAC address after parsing. a computer with another IP address of computer communication, the ARP cache will be retained in the corresponding MAC address. So the next time and the same IP address, computer communications, will not MAC address of another query, but direct reference to the MAC address of the cache. Also, to note that, through the \after the start, these items will be deleted. Therefore, even if you cancel a bind, in a short time the other computer will still think you are the original IP addresses used.
in the switched network, the switch has to maintain a MAC address table, and according to MAC address to send the data to the destination computer. when binding IP and MAC address, as long as the communication with the switch off, the switch will record the MAC address. Thus, even if the back was used the same IP address, will still not work with Gateway Communications, but even outside the barrier, unless the re-start the switch, clear the MAC table, or exceeds the specified MAC address table aging time
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LAN is HUB 10Mbps Ethernet connection, why file transfer only when prompted 800KB ~ 900KB / s of transmission
This is because the rate measured in different ways.
one is Bit bits, a byte is Byte . usually there in a Byte 8 Bits. network bandwidth is usually bps (nominal bit / s) as the unit of measurement, that is, \Special rates) \
hub restrictions. hub is 10Mbps shared bandwidth, if all ports are in communication state, the available transfer rate per port per second 0.625MB (calculated as 10d16). wants to be close to the theoretical obtained bandwidth transmission rate, the switch must be used as a set of line equipment.
card reasons. If card quality is not good, given the data packets are often wrong, resulting in frequent retransmissions of data packets, or receive more data packets of the wrong would lead to lower speed copy paper.
causes the wire. If the cable is too long, more powerful signal attenuation, or although the network cable from the past, but the poor quality cable can not reach theoretical speeds. In addition, When the network busy, they failed to achieve the speed.
20,
Q: 7 users to connect through the switch and is ready to help the routing function to achieve ADSL Modem Internet Connection Sharing. ISP provides a fixed IP address, network card’s MAC address and will be binding, and the boot can access Internet, rather than the virtual dial-up. I ask, should be how to configure the ADSL Modem Internet Connection Sharing can be achieved?
A: If the IP address and ISP network card The MAC address binding together, is the routing ADSL Modem function can not be shared online. The reason is simple, each card has a unique MAC address, so other computers connected to the Internet access will be denied. the only The solution, only the ADSL Modem to connect to the ISP that has been bound MAC address of the computer, and set the computer for the proxy server, the other computer as a client-side to achieve Internet Connection Sharing.
21, Q : How to use VPN to make another visit to two local area network through the Internet? tried a machine with Modem dialing mode with the VPN can access LAN, but only found the server, do not see the other machine, why? < br> Answer: First of all be explained, VPN main role is to a client remote access VPN server or VPN server through the VPN server to access the host network. 2 LAN access each other through the Internet computer network, can only do VPN routing .
If a remote access VPN server and client where the network needs to properly configure the VPN server, mainly for remote VPN server assigned IP address of client problems. When the VPN server and the DHCP server when not on the same computer , you can use the DHCP mode for the remote client IP address assigned; when the VPN server and the DHCP server on the same computer, you can only use a static address assignment method, the \br> After the dial-up can not access the LAN, is not assigned to the LAN IP address legitimate. In addition, when using the VPN dial-up, dial-up client must have a valid IP address, or dial VPN server is meaningless.
settings VPN route connecting two LAN, both sides in the VPN server, \The IP address, you can create a static route (in the \; to add \. At this point, can be no legitimate IP address of the VPN server using dynamic DNS software and applications for a domain name for this VPN server, VPN server on the client can dial this domain.
——< br > Gateway occupies 80 port
Q: I have set up the server for the Windows 2000 Server Edition operating system, open a WWW, DNS, FTP (SERV-U), E-mail (Web EasyMail) services. specified private IP address \server. Web server on port 80, but still can not access. Later, I added in the Web in 81 ports, IP-81 through the external network port can have full access to the Web page. this is need to set up port mapping (Server Adapter is a single RJ45/10Mbps LAN interface)? gateway settings will not be a problem?
A: From your question point of view, should be your gateway takes up 80 ports, and \port, through the external network IP’s 81 ports can have full access to the Web page \> determine whether a server failure, you can use the substitution:
① to look for workstations, install only the IIS (default installation), and install a network card (set 172.16.108.a and gateway is set correctly), use this platform temporary replacement of your server computer, Internet access 218.106.98.b out to see the success, if it shows you where failure, or failure at the gateway.
② you this computer from the network on a temporary break open, install a Modem, dial-up Internet access, and then in the command window, enter ipconfig, see your access to the external network address, so that other people inside IE to access your dial-up Modem access to this IP address to see whether the visit, if the description no fault of your computer; if not, then the interruption in the computer (if your IIS settings specified address, change to the correct address, that is, Modem dial-up access to the address after).
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Dual permission issues directly connected
Q: Two installed Windows XP system laptop connected using twisted-pair straight, the connection unstable, and often can not browse the other computer, and even the working group are to play not open, it says \?
A: It must address the IP address and user rights issues, has the following methods:
First, give each a laptop set up a private IP address, such as the one for 192.168.1.10, the other is 192.168.1.20, subnet mask is 255.255.255.0. or use both \address.
Second, each laptop to enable \using the right pane, right-click \\sharing (recommended) \Fifth, in the \Then, open Windows Explorer, set the shared folder.
NETBIOS and browse Network Neighborhood Network Neighborhood Analysis
the question from people who have been more, there’s errors in understanding are generally more serious. Given Microsoft’s NETBIOS documentation is not very detailed, I collected over some relevant information with their own practical experience to write this series, I hope you can help.
originally intended to increase readability, this series was into a question and answer form, but also a moment his head could find so many problems, or the first emotional step by step on Microsoft’s browsing service as a general introduction, and then in-depth analysis of the specific working mechanism NETBIOS, If you have any questions can be made to discuss with us.
program divided into three sections concerned, the process of Microsoft’s Web browser, NETBIOS depth analysis, and network configuration details
*** Microsoft’s Web browser in the course Introduction ***
\can not access or can access not see? Please choose the best answer: A. Your Web presence of physical problems, such as cable B. as the domain master browser for Windows NTserver browsing service bad card there is the problem C. Windows NTserver D . your network no problem, the user describes the phenomenon of the normal Microsoft Explorer
correct interpretation of the book answers
: Microsoft’s Web browser may use a \interruption, this misconception is due to Microsoft’s Web browser users are not familiar with the processing result.
as students often complain about the \Why sometimes can browse, and sometimes can not browse the network? \also do not quite understand the concept, there are many here fault the machine was 98, I will be 98 \Users can browse the list to see the entire network (that mean? subnet or broadcast domain? we can think about it) on all computers. When you have passed the network window opens My Network Places, you will see a list of working group , and then open a working group, you will see the inside of the computer list (also Zai Xia DOS mode to use net view / domain: workgroupname order Dedao), which is Womensuoyue the Browsing List. Working Group that is the essence share a browse list of a group of computers, all are equal between the working group, no provision can not be the same for all computers in a workgroup.
2. browse the list of where to watch in kapok been to a dispute, it was said: My Network Places in the computer list is broadcast queries come. can someone give counter-examples, said: My classmates are off, but I can still see it in My Network Places where it should be from HUB or switch, like a more permanent equipment acquired in the cache. In fact, they say only one side, to say the two of them together is the correct answer — browse the list of broadcast queries for browsing through the master server , provided by the browse master servers.
3. Browse Master, what is the Browse Master is a working group of the most important computer, it is responsible for maintaining the working group browse list and specify other Working Group of the master list of servers, and other computer-based working groups and other visitors of this working group to provide computer browsing services, each working group will have to select a view for each transport protocol master server, and we often encounter The error can not browse the network in which most of the working group because you did not visit the master server caused. You can used in a working group NBTSTAT-a computername command to find the master browser using the NBT protocol server, it logo containing \ \ _MSBROWSE_ Name field.
4. browse the master server is how to specify the default, win98 working group visit the main …
LAN troubleshooting common questions and answers
July 30th, 2010 by admin
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