How to solve the problem that IP addresses cannot access the Internet

This article mainly introduces in detail how to solve the problem that the IP address cannot access the Internet. I believe this article will be helpful to you.

As the saying goes, "All birds and birds are there." When the network size of the LAN is getting bigger and bigger, all kinds of network faults may occur. This is not the case. I have encountered such a strange fault: In the office network, computers using fixed IP addresses suddenly cannot access the Internet, computers that use the "automatically obtain address" method can access the Internet normally. This fault has a special cause. To help your friends accumulate online experience, this article will explain and restore the detailed troubleshooting process of this special fault, I hope you will be inspired by the following content!

Some hosts cannot access the Internet due to IP address faults.

Due to work requirements, I have not connected several computers in my office to the LAN or directly access the Internet through the LAN. Instead, I share the ADSL Router, dial-up connections to the municipal e-government intranet, and all computers connected to the E-Government Intranet are not allowed to access the Internet at ordinary times, so as to prevent various viruses and trojans from the Internet from attacking the e-government intranet. To facilitate network management, the network operator enabled the DHCP service feature provided by the ADSL Router device, and set the address pool parameters. After testing, all the computers in the office can normally obtain the IP address range 192.168.0.10-192.168.0.50 and access the e-government intranet normally.

After the parameters of the DHCP server are configured, any client computer can access the municipal e-Government Intranet by setting it to "automatically obtain IP addresses". However, two colleagues who are a little familiar with the Internet think that when using dynamic addresses to access the Internet, the system starts slowly, so they make their own claim to change their computer's Internet address to a static address, A colleague sets his computer's Internet address to 192.168.0.16, and another colleague sets his computer's Internet address to 192.168.0.33. In normal times, all computers in the office can smoothly access the data in the municipal e-government intranet through static addresses or dynamic addresses, and the Internet access speed is also very fast. However, from one day, a strange phenomenon occurs in the office network. Some computers can access the Internet normally, while others cannot access the Internet normally; after careful investigation on the faulty site, the network administrator found a shocking secret that computers that can access the Internet normally use dynamic addresses without exception, and those computers that have failed to access the Internet, these two computers use fixed IP addresses.

IP address Fault Location

The Network Administrator has his own understanding of the fault. He thinks that since computers using dynamic addresses can access the Internet, the working status of the ADSL Router in the office network is normal, otherwise, these computers that can access the Internet cannot obtain valid parameters from the DHCP server. In this case, the problem lies in the faulty computer system itself? The Network Administrator's mind first showed that the faulty computer may have a network virus, because the computer can access the Internet normally before it fails, and other computers in the office can access the Internet normally. Now the faulty computer has a problem, therefore, there is a lot of suspicion about network viruses. After all, many computers infected with Network Viruses may suffer any faults. To verify whether the network virus is "innocent", the network administrator decided to first scan and take a look at the virus, so he immediately found the latest version of anti-virus software, and took the trouble to install and disinfect the virus, after a period of virus detection, there are still some gains. The viruses hidden in the "Corner" of the faulty computer system have been "evicted" relentlessly, looking at these constantly cleared Network viruses, the network administrator has a little hope. Is the problem really caused by the hidden network viruses? However, after an online test, the network administrator found that the computer with the virus cleared still could not access the municipal e-government intranet, and the fault phenomenon was the same as before, obviously, the network virus is not the "culprit" that fails to allow computers to access the e-government intranet ".

After proving that the network virus is "innocent", the network administrator had to reluctantly "blame" the problem for physical connections. After all, there is a high possibility of an unexpected physical connection. In order to worry that the network connection cable of the computer may be broken or short-circuited, the network administrator specially found a professional network cable tester to test the connection status of the target network cable, the test showed that the Network cables of the two computers were not connected. To prevent the contact between the crystal head at both ends of the network cable and the switch or computer from being unreliable, the Network Administrator carefully pulls out the crystal head inserted into the switch and the network card, then, re-insert it to the RJ45 port according to the correct method until the switch port or the signal on the NIC device flashes. However, when the network administrator attempts to access the e-government intranet from the faulty computer, the access operation is still unsuccessful, but it is normal to ping the IP address of the server host from the faulty computer system, this indicates that the failure of the client system to access the Intranet is not related to the connectivity of the cable.

Is there a fault in the client system itself? However, the possibility of two client systems having problems at the same time is not very high. The problem must be on the network cable and the switch port. To eliminate these possibilities, the Network Administrator deliberately uses his laptop to temporarily replace the faulty client system and perform an online test. The test result surprised the network administrator that the laptop can access the Internet normally. Comparing the network access parameters of the laptop and faulty client systems, the network administrator can see that the laptop uses a dynamic address, while the faulty client system uses a fixed address, is it true that I cannot access the Internet normally when I use a fixed IP address? After confirming that there is a problem with the IP address settings, the network administrator tries to set the IP address of the faulty Client System to "automatically get the address". As a result, the client system can access the Internet immediately after the fault occurs, it seems that the problem is indeed caused by improper IP Address Settings.

IP address faults

Although the faulty client system can access the Internet through dynamic addresses, the network administrator is still confused about why the faulty client system can smoothly access the content in the E-government intranet using static IP addresses, what if I keep the original static address but cannot normally access the e-government intranet? For such a fault, the Network Administrator carefully considers whether the DHCP server in the office Intranet has changed since the Dynamic Address can access the Internet and the static address cannot access the Internet, as a result, the IP addresses dynamically allocated to the client computers also change, and those computers that have been using static addresses will not be those whose Internet addresses remain unchanged, what about the failure of accessing the e-government intranet? According to this analysis, the network administrator checks the Intranet of the office to check whether a DHCP server is added or the original DHCP server has changed; because the original DHCP server is provided by the ADSL Router device, the network administrator wants to remotely log on to the background system of the adsl Router device through Web, and check whether the DHCP service settings have been moved. However, when the network administrator opens the IE browser and enters the default address "http: // 192.168.0.1" of the ADSL Router device, it finds that the background system page of the device cannot be opened. What is the problem? What's more, my laptop can access the Internet normally? The Network Administrator attempted to access "http: // 192.168.0.1" from several other client systems that can access the Internet, but the IP address of the router cannot be pinged by using the ping command, is the default IP address used by the ADSL Router device changed? Later, the network administrator asked several employees in the office that they had not moved the ADSL Router equipment. When the network administrator was unable to do anything, another employee who had just been on a business trip from other places came in, after learning about the fault, he immediately said that he had changed an ADSL Router. The former ADSL Router was used elsewhere.

Later, the network administrator found the new ADSL Router device. The default IP Address used has changed to 192.168.1.1. after entering the background page of The New ADSL Router device with the "http: // 192.168.1.1" address, the network administrator can see that the DHCP service is also enabled on the vrodhcp, but the address pool parameter is not set. In this case, the DHCP server will automatically assign the IP address range 192.168.1.0 to all client systems in the office Intranet, and the faulty client systems that use the fixed IP address are in the IP address range 192.168.0.0, in this way, the client system with a fixed address will naturally be unable to access the Internet. When these faulty client systems use dynamic addresses, they can obtain the IP address range 192.168.1.0 from the DHCP server. In this case, the failure to access the e-government intranet will naturally disappear immediately.