Summary of the problems that QQ can use and web pages cannot be opened

Summary of the problems that QQ can use and web pages cannot be opened
Many netizens once mentioned to me the problem that the web page cannot be opened when QQ can be accessed. In fact, there are many reasons for this problem. I will summarize the various methods and experiences on the Internet.
　　
First of all, we need to know that the protocols used for internet access are generally TCP/IP, and all IP protocols are called internet protocal, which is located at the Layer 3 (Network Layer) of the OSI Layer 7 protocol ), layer-4 (Transport Layer) protocols based on the IP protocol include TCP and UDP. The web browser we usually use to access the Internet is working on TCP, while QQ is working on UDP (but sometimes qq also calls tcp, which won't go deep here ). Knowing this is important.
　　
Now that we know how it works, we can naturally make the following bold estimates: normal use of QQ indicates that UDP is okay and web pages cannot be viewed. The problem may be caused by TCP. Check the content about TCP Communication Principles in windows online, and find the most common cause: Winsock error.
　　
Cause 1: The WinSock component is damaged.
　　
WinSock is a network programming interface of TCP/IP in windows. It encapsulates a large number of common network-related APIs for point-to-point network communication. Once the WinSock function module is damaged, it may cause problems for network communication. About 80% of web pages cannot be opened on QQ are damaged by the Winsock component. There are several causes of component damage: virus causes, incomplete anti-virus software virus sequelae, Pirated Windows XP, operating system patch installation faults, and abnormal system restoration. You can first install and shut down the Windows disk into the optical drive and run the sfc/scannow command to fix it.
　　
There is also a dedicated tool on the Internet: Winsock Fix. If a problem occurs, use this tool to fix the problem and restart the instance.
　　
Cause 2: domain name resolution Error
　　
1) when a computer performs domain name resolution, it first needs to access the Hosts file of the Local Machine. Generally, some viruses will modify this file to shield some websites, especially anti-virus websites (See Supplement ). The Hosts file is in the user's system directory. The default value is "C: \ Windows \ System32 \ Drivers \ etc". We can open it with "Notepad. Generally, the content below "127.0.01 localhost" does not exist, so it can be deleted.
　　
2) Check the settings of the DNS Server, such as "nslookup www.baidu.com". If the returned information is "Default Server: UnKnown", it must be because the DNS Server has a problem. In this case, you can go to another person's computer and use ipconfig/all in CMD to view the correct DNS. Then, enter the correct DNS value in the IP Address Configuration window.
　　
3) Another possibility is that the local DNS cache is faulty. To speed up Website access, the system automatically saves a website that has been accessed and obtained an IP address to the local DNS Cache. Once the website is accessed again, then, the IP address of the website is not directly retrieved from the local DNS Cache through the DNS server for access. Therefore, if a problem occurs in the local DNS cache, the website cannot be accessed. You can execute ipconfig/flushdns in "run" to recreate the local DNS cache.
　　
Supplement: the host file is used to block the specified website address. The principle is that when a computer performs domain name resolution, it must first check the entries in the host, similar to the cache, to find the corresponding entries, if you directly use this entry, you will not query it through the DNS server. Therefore, to shield www.sina.com.cn, you only need to add www.sina.com.cn 127.0.0.2 to the host. What does it mean? When we enter www.sina.com.cn in the browser, the computer will check the host, find the entry written above, and then access 127.0.0.2, which is the local loopback address, that is, it corresponds to the current computer. In this way, the sina server is your own computer, which of course cannot get the correct response.
　　
Cause 3: Improper proxy settings
　　
When browsing some web pages, it may be inexplicable to automatically set the proxy, or if you have used a proxy for a long time, everything works normally, so you will forget the existence of the proxy, and the proxy will become invalid one day, you cannot access the Internet. Don't you think it's a proxy problem if you scratch your head? So pay attention to this. You can delete the proxy or use a normal proxy to restore the normal operation.
　　
Cause 4: the browser is damaged.
　　
Generally, we use IE or IE-based browsers. If IE is broken, What are other normal functions? Can I browse webpages? How can I determine if IE is damaged? In addition to Winsock, domain name resolution, proxy, and other issues, you can try to use firefox, opera, and other non-IE core browsers. If you can access the Internet normally, it indicates that there is a problem with IE. You can solve the problem by reinstalling it.
　　
In windows XP, IE6 cannot be reinstalled by default. You can fix it as follows:
　　
First, prepare the Windows XP installation disc and insert the optical drive. In the "Start/run operation" window, enter the "rundll32.exe setupapi, InstallHinfSection DefaultInstall 132% windir % \ Inf \ ie. inf" command, and press enter to reinstall IE.
　　
You can also open registry editor and expand [HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Active Setup \ Installed Components \ {89820200-ECBD-11cf-8B85-00AA005B4383}], change the IsInstalled DWORD value to 0 to reload IE from "add and delete programs.
　　
Cause 5: Firewall Blocking
　　
Some anti-virus software or firewall network access rules (such as access rule settings in Rising's network firewall, IP access rules in Kingsoft's network firewall, etc ), if Windows Explorer and Interner Explorer are prohibited from accessing the network for various reasons, the problem of "accessing QQ but not accessing the Internet" may also occur.
　　
Cause 6: ApplicationManagement Problems
　　
When the web page cannot be opened only on QQ, You can restart it. However, even if it is restarted, after opening 7 to 8 web pages, you can only go to QQ. Sometimes China Telecom often allows you to disable the ApplicationManagement service. The specific cause is unknown.
　　
Cause 7: Other Cases
　　
1) virus infection.
　　
2) unable to open, prompt webpage download error, enter in start-run:
Regsvr32/s Softpub. dll
Regsvr32/s Mssip32.dll
Regsvr32/s Initpki. dll
Regsvr32/s Wintrust. dll
Restart IE to solve the problem (the last dll can be reloaded and processed as appropriate)
　　
3) Another phenomenon also needs to be paid special attention: the homepage of the website can be opened, but the second-level link cannot be opened. If so, the solution is to re-register the following DLL file:
Enter:
Regsvr32Shdocvw. dll
Regsvr32Shell32. dll (note that you do not need to enter this command First)
Regsvr32Oleaut32. dll
Regsvr32Actxprxy. dll
Regsvr32Mshtml. dll
Regsvr32Urlmon. dll
Regsvr32Msjava. dll
Regsvr32Browseui. dll
　　　　
Note: Press ENTER for each entry. The second command does not need to be input. After these commands are input, restart windows. If it is invalid, enter the second command again.