Network faults and Techniques

DNS proxy fault

Reader KAIX: There is a dial-up service and a domain management server in the company's network. When dialing, ping commands always cause packet loss. After the DNS proxy is canceled, the situation immediately becomes normal. QQ connection is normal, but the webpage cannot be opened. What is the possible cause?

Since the problem can be solved after the DNS proxy is canceled, it is estimated that there is a problem with the DNS proxy or the selected DNS server. In fact, no matter which proxy server or firewall is used, you can directly use the Internet DNS server as long as the DNS port communication is allowed, instead of using the DNS proxy. In addition, since QQ can be connected, but cannot access the Web site, it indicates that there is no problem with the Internet connection, and the cause of the failure is naturally a DNS resolution failure. In fact, QQ can directly specify the IP address of the server without DNS resolution.

Crash caused by Internet access

Reader's view: My computer is connected to the Internet through ADSL. It works normally if you do not access the internet. As soon as you access the Internet, the computer will soon crash. Only restart by Reset. The computer is TCL Ruixiang K3681. Modem is Huawei SmartAX MT800. The system is Windows XP and uses the star 2.0 client. It is useless to reinstall the system and NIC Driver. What should we do?

There are many causes for computer crashes. We recommend that you use the following methods for determination:

First, let ADSL dial-up connect to the ISP, but do not open IE or run Internet applications such as QQ. If it can run stably without crashing, it means there is no problem with the Internet connection.

Second, if an ADSL dial-up fails, it means that ADSL is incompatible with the computer. It may be a NIC or ADSL hardware fault, or a PPPoE protocol or driver software fault. Possible measures include:

* Uninstall the star 2.0 client and use the built-in ADSL dialing program of Windows XP.

* Set ADSL to the routing mode instead of the virtual dialing mode.

* Change the NIC slot or the new Nic.

* Change the ADSL Modem.

Third, if the system crashes when you open Internet Explorer and browse the Web page, it indicates that there is a problem with Internet Explorer or the operating system. We recommend that you reinstall or fix the system.

Fourth, it may also be infected with the worm. We recommend that you install system patches and virus firewalls.

Unable to display custom expressions

Reader ajksd: When I send or receive custom expressions on QQ, there will be a "card" phenomenon. It will take a few minutes. However, the User-Defined expressions and Images cannot be received by the other party. After you turn off the firewall provided by Skynet and Windows, try again. What is the possible cause? What should we do?

The cause of this failure may be that the Internet connection speed is too slow. We recommend that you change the Internet access mode or Internet sharing mode. When a proxy server or a broadband route is connected to Internet, the image cannot be received and displayed. You can change the broadband Internet access mode, such as ADSL or residential broadband, or cancel the Connection Sharing Mode of proxy at or above level 2, or even try to directly dial the Internet. If the problem is solved, the problem is caused by Internet access.

Homepage modified by malicious website

Reader diker: After a website is linked through a search, the website automatically becomes my home page, and the home page items in the Internet Options become the site, which is grayed out. When I use QQ to chat, every time I start chatting with people, there is a saying, "Why do you scold me? Where did I provoke you? I hope you will be responsible for your messages. You can explain to me, http: // malicious website URL ". Later, the StartPage Key Value Name (used to set the default homepage) in HKEY_LOCAL_USER \ Software \ Microsoft \ InternetExplorer \ Main was modified by manually modifying the registry. What should I do?

The cause of the failure is that the Script Vulnerability virus is infected. You can use the new versions of Symantec and KV2005 to clear the vulnerability, or use the netassistant of 3721 to solve the problem. Because many viruses have set registry recovery in the auto-run key value, it is not enough to modify the above key value, you must also view and modify the HKEY_LOCAL_MACHINE \ Software \ Microsoft \ Windows \ CurrentVersion \ Run item to delete unnecessary applications. In addition, we recommend that you upgrade Internet Explorer to 6.0 + SP1 and update the system patch. Note that if the system is Windows 98, you must upgrade it to Internet Explorer 6.0 + SP1. if the system is Windows 2000/XP, you must upgrade the system patch in time.

As a temporary solution, you can use the "Notepad" program to modify the c: \ WINDOWS \ system32 \ drivers \ etc \ hosts file and add the following line to it:

127.0.0.1 the URL of a malicious website or change 127.0.0.1 to the IP address of another default homepage.