ADSL FAQ and Fault

1. ADSL FAQ Classic Fault





ADSL is running on the original telephone line of a high-speed broadband Internet access, it has the advantages of saving investment, fast Internet, simple installation and so on. At present, many local area networks, especially Internet cafes, use this method. Of course, the Internet in this way the fault is also more, the following for everyone to talk about ADSL troubleshooting methods and examples.





the factors that cause ADSL fault




The common hardware faults of
ADSL are the problems of joint loosening, cable breaking, hub damage and computer system malfunction. It is generally possible to use the observation LEDs to help locate.





in addition, the voltage is not normal, the temperature is too high, lightning, etc. also easy to cause trouble. Voltage instability where the best for the modem with small power ups,modem should be kept dry and ventilated, avoid water, keep clean. In the event of thunderstorm, be sure to unplug the modem power and all connections. Modem damage If the LED is not lit, or only one light, or replace the network cable, network card after the 10BASE-T lamp is still not lit, it indicates that the modem has been damaged.





line distance too long, poor line quality, wiring unreasonable, but also caused ADSL can not use the normal reasons. Its performance is often lost synchronization, synchronization difficulties or slow consistency. The solution is: will need to connect the equipment such as telephone extension, fax, general modem, etc. put to the phone mouth of the distributor after: Check all the joint contact is good, poor quality of the household line should be transformed or replaced.




The basic method of
locating ADSL fault





ADSL fault location needs a certain experience, the general principle is: pay attention to indicators and error information, hardware software after the first, the internal external, first local after the net, first test the host after the customer, full inspection and then declare. Failure reporting should be accurate and concise, should be encountered as far as possible the problem with the user manual mentioned in the corresponding fault. When reporting a failure to the engine room, the port number and user name should be reported first according to the user manual. For frequent breakdowns, the user should record and refer to the declaration.





1. Check that the power LED is normal




The
power LED is located at the far left of the 3 LEDs on the user's modem and continues to light up as normal, such as the power LED is not lit and the user can solve the power problem on its own.





2. Data LED is normal





data indicator is located in the user Modem 3 lights on the right two, continued to light as normal, indicating that the user end to the Dslam side of the line without fault: If the indicator light is not bright, indicating that there are problems in the line, the telecommunications sector needs to be resolved on-site.





3. Whether the user changes the IP address





each user PC has its fixed IP address, if the user changes its address, the Telecommunications department can provide its PC IP address, the IP address can be changed back.





4. User network card, network cable is normal





User PC network card connected to the modem after the cable, the indicator lights flashing, such as the light can not be normal flashing, indicating that the user network card or network cable failure.





if all of the above are normal, users still do not have access to the Internet, you need to be resolved by the ISP's technical staff.





fault Diagnosis Processing instance





1. The computer on the local area network cannot use PPPoE





[Symptom]





an ADSL connection uses the 10/100MB/S hub, while computers on the local area network are not able to use PPPoE.





[fault analysis processing]





ADSL uses the 10BASE-T standard namely 10MB/S, it connects 10/100MB/S's hub is not the problem, but if the computer and the hub connection speed is 100mb/s,hub 10/100mb/ Sjiao Swap module is currently not very good for PPPoE support, then PPPoE may not be able to find ADSL signals under 100mb/s speed, you can not use. The solution is for PPPoE dial-up computers to use the 10MB/S wiring method to make 10MB/S network cable, or to force the network card to work at 10mb/s speed.





2. When the data flow is large, there is a panic





[Symptom]





An ADSL, when the data flow increases will panic.





[fault analysis processing]





in general, this is due to the quality of the NIC or bad compatibility caused, especially the old ISA bus IOM network card, because PPPoE is a relatively new technology, this type of network card compatibility may be problematic, and slow, resulting in conflict, the final line lock dead, or even panic.





3. Startup speed slows after installing PPPoE





[Symptom]





installed the ADSL PPPoE software after the computer startup speed is slow.





[fault analysis processing]





this and network card settings have problems, because the system needs a legitimate IP, the local area network needs to set up a DHCP server, if it is a stand-alone use of the network card to assign an IP, you can solve the problem, For example: 192.168.xxx.xxx, subnet mask: 255.255.255.0.





4. The ISP's service items cannot be listed





[Symptom]





PPPoE software installs and works properly, but does not list ISP service items.





[fault analysis processing]





first check the hardware connection is correct, ISP is providing services, these can be observed in the ADSL modem sync work lights display status to judge, if the sync work lights display normal work, then check whether other devices in the computer interference ADSL work, and the driver upgrade. Also need to pay attention to is whether the ISP opened the corresponding services, because ADSL there are some special numbers bundled in the telephone jiao, the ISP need to authenticate these numbers can be considered as the user's line is legally available, and ISP's ADSL access server is not open, it is not possible to list server projects.





5.ADSL internet speed Slow





[Symptom]





Sometimes ADSL access speed is not much faster than the normal dial-up modem.





[fault analysis processing]





caused ADSL access speed is slow, the main reasons are:





1 If you visit a foreign site, the access will be affected by factors such as export bandwidth and the configuration of the other site.





2 ADSL technology for the quality of the telephone line requirements higher, and the current use of ADSL is a RADSL (Rate adaptive ADSL), if the telephone company building to the user's phone line in a certain period of time by external factors interference, RADSL will dynamically adjust the user's access speed according to the quality of the line and the distance of transmission.





6. Sometimes not networked





[Symptom]





ADSL sometimes does not have the normal Internet.





[fault analysis processing]





ADSL is a technology based on twisted pair transmission, the twisted pair is to tie two insulated copper wires together with certain rules, which can effectively resist the external electromagnetic interference. Most telephone lines are parallel lines, from the Telephone company junction box to the user phone line is mostly used parallel lines, this is very unfavorable to ADSL transmission, too long non twisted wire transmission will cause connection instability, ADSL flashing lights and other phenomena, thus affecting the Internet. Because ADSL is in the ordinary telephone line low-frequency voice superimposed high-frequency digital signal, so from the telephone company to the ADSL filter this connection of any device will endanger the normal transmission of data, so before the filter and answer the phone, telephone anti-theft device and so on.




The
7.ADSL LEDs are normal but still off the net





[Symptom]





an ADSL LED is green, but also the phenomenon of drop line, and restart the modem after the good.





[fault analysis processing]





This happens when there are no proxy servers, no firewalls, or network users without routers. This is because there is a "lobase-t" port on the Adslmodem, this port is the hub port of the LAN. Although it is a 10mb/s port, the uplink bandwidth of ADSL is only hundreds of kb/s. If the user LAN internal is ADSL directly connect Hub,hub and then the following client, the network of many ADSL-independent packets will occupy ADSL uplink channel, ADSL also can not control the local area network broadcast storm; if more than ADSL uplink transmission capability, packets will be loaded into the ADSL cache If the data volume continues to increase, the cache overflow, the ADSL "sleep" phenomenon. This only restarts the modem. The solution is to do a dual network card proxy server, so you can cut off the modem and the local area network direct communication, to avoid the above problems.





8. Virtual Dialing failed





[Symptom]





ADSL When you use virtual dial-up software, you are prompted for an error message and the dialing fails.





[fault analysis processing]





If the dial-up window displays "Begin negotiation" and then waits, the last direct Dan out of the menu "Time Out" indicates that the network is out of order. The main reason is ADSL on the 10BASE-T port cable is not connected or ADSL network, you can restart ADSL and then try again.





If the dial-up window displays "Begin negotiation" and then displays "authenticating", then "Authentication Failed" is displayed, which indicates that the user account or password is incorrect.





If the dial-up window displays "Begin negotiation" and then displays "authenticating" and then displays "Receiving network Parameter", the last Dan out menu "Timeout", This situation indicates that the Dial-up IP address is already full and needs to be dialed later.





2. The ten ways of ADSL defense hacker attack





At present, the use of ADSL users more and more, because ADSL users online long, fast, so hackers are targeted. Now there are a variety of more and more detailed "IP address library", to know some ADSL users of the IP is very easy things. How to defend your network security? Consider the following methods.





folder hidden share





If you use the Windows 2000/XP system, right click on C or other disk, choose "Share", you will be surprised to find that it has been set to "Share this folder", and in the "Network Neighborhood" is not see this content, what is this?





originally, by default, Windows 2000/xp opens a hidden share of all partitions, selecting System Tools/Shared Folders/shares under the Control Panel/Administrative Tools/Computer Management window to see that each partition name on the hard disk is appended with a " contentrdquo;. But as long as you type "computer name or ipccontentrdquo;, the system will ask the user name and password, unfortunately, most of the personal User system administrator's password is empty, the intruder can easily see the content of C disk, which brings great potential for network security."





how to eliminate default sharing? The method is simple, open Registry Editor, go to "hkey_local_machinesystemcurrentcontrolsetseviceslanmanworkstationparameters", and create a new name called " AutoShareWks, and set its value to "0", then restart the computer so that the share is canceled.





II, reject malicious code





malicious Web pages have become one of the biggest threats to broadband. Before using the modem, because the speed of opening the Web page is slow, before completely open the malicious Web page and avoid the possibility of the recruit. Broadband is now so fast that it can easily be attacked by malicious Web pages.





generally malicious Web pages are because of the addition of malicious code written to be destructive. These malicious code is equivalent to some small program, as long as the page is opened to be run. So to avoid malicious Web page attacks as long as the prohibition of these malicious code to run it.





Run IE browser, click "Tools/internet Options/Security/Custom Level" to define the security level as "security level-high", set the 2nd and 3 items to "disabled" in ActiveX controls and Plug-ins, set the other items to "prompt", and then click OK. This setting, when you use IE to browse the Web page, you can effectively avoid malicious Web page malicious code attacks.





three, the "backdoor"
of the hacker's death




as the saying goes, "smoke", since hackers can enter, that means that the system must exist for them to open the "back door", as long as blocking this backdoor, so that hackers have nowhere to go, there will be no worries!





1. Eliminate unnecessary Protocols





for servers and hosts, it is usually sufficient to install only the TCP/IP protocol. Right-click Network Neighborhood, select Properties, right-click Local Area Connection, select Properties, and uninstall unnecessary protocols. Among them, NetBIOS is a source of many security flaws, and for hosts that do not need to provide file and print sharing, it is possible to turn off the bindings in the TCP/IP protocol NetBIOS to avoid attacks against NetBIOS. Select TCP/IP protocol/Properties/advanced to go to the Advanced TCP/IP Settings dialog box, select the WINS tab, and uncheck "Disable NetBIOS on TCP/IP" to turn off NetBIOS.





2. Turn off file and print sharing





file and print sharing should be a very useful feature, but it is also a good security breach for hackers when it is not needed. So without the need for "file and print sharing," we can turn it off. Right-click Network Neighborhood, select Properties, and then click the File and Print Sharing button to remove the hooks from the two check boxes in the File and Print Sharing dialog box for Dan.





Although file and print sharing is turned off, it is not guaranteed to be secure, and the registry is modified to prevent people from changing file and print sharing. Open Registry Editor, select the "Hkey_current_usersoftwaremicrosoftwindowscurrentversionpoliciesnetwork" primary key, and under the primary key, create a new DWORD type key value named " Nofilesharingcontrol ", the key value is set to" 1 "to prohibit this feature, so as to prohibit the change of" File and Print sharing ", the key value of" 0 "to allow this feature. This removes file and print sharing from the Properties dialog box in Network Neighborhood.





3. Disable the Guest account





has a lot of intrusions through this account to further obtain the administrator password or permissions. If you don't want to give your computer to others as a toy, it's a good ban. Open Control Panel, double-click Users and Passwords, click the Advanced tab, and then click the Advanced button and Dan out the Local Users and Groups window. Right-click on the Guest account, select Properties, and choose "Account deactivated" on the "General" page. In addition, renaming the administrator account can prevent hackers from knowing their administrator account, which will largely guarantee computer security.





4. Prohibit the establishment of an empty connection





by default, any user can connect to the server via a null connection, enumerate the accounts, and guess the password. Therefore, we must prohibit the establishment of an empty connection. The method has the following two kinds:





method One is to modify the registry: Open the Registry "Hkey_local_machinesystemcurrentcontrolsetcontrollsa", the DWORD value "RestrictAnonymous" The Key value of "1" can be changed.





finally recommended that you put a patch on your system, Microsoft's endless patches are still very useful!