Exclude ADSL dialup failure under Linux

I believe most of my friends are using ADSL dial-up Internet access in Windows environment. In this environment, if you are unable to dial-up Internet access, you can search online according to the fault phenomenon. It is very convenient to find a solution to the problem. However, some friends often need to conduct ADSL dial-up Internet access in the Linux environment for their work needs. When encountering a fault phenomenon in this dial-up environment, I believe most people will be unable to do anything. In fact, we still have rules to follow when troubleshooting ADSL dialups in Linux environments. This is not, when we are unfortunately encountering ADSL dial-up Internet failure in the Linux environment, we can try to check one by one according to the following method, I believe that the fault can be solved quickly and effectively!

When encountering ADSL dialup failure, the first thing we need to do is to upgrade the PPPOE dialer in time to let it work in the latest version, because of the speed of ADSL dial-up Internet under the new version of the dialer. Stability can be guaranteed.

Generally speaking, the version of PPPOE dialer in Linux environment should be higher than 3.5-1. If we find that the version of dialer currently used is lower than this version, we can download it online to get the latest version of PPPOE. Dialer, assuming the new version of the PPPOE dialer is named rp-ppoe-3.5-3.i386.rpm, then we can execute the string command in the command line of the Linux environment. rpm Uvh rp-ppoe-3.5-3 .i386.rpm", so that the PPPOE dialer in the Linux environment can be upgraded to the latest version.

Considering that ADSL equipment is often directly connected to network card equipment, before direct dial-up Internet access, we often create a point-to-point communication link on the Ethernet through the PPPOE dialer. This link is the PPP link we usually mention. Therefore, when we confirm that the PPPOE dialer is in the latest version state, if the ADSL dial-up Internet still fails, then we should carefully check whether the PPP link is normal.

When checking whether the PPP link is normal, we can first execute the “ifconfig -a” string command in the command line of the Linux environment. Through this command, we can find out whether the network connection interface of the local workstation is Already in the startup state, but also know whether the local network card has been bound to the appropriate IP address. If the PPPOE connection interface of the local workstation is not started, we can execute the “ifup PPP0” string command to restart the PPP0 network interface on the local workstation.

If the default IP address of the ADSL device is not yet bound to the NIC device of the local workstation, then we may wish to execute “ifconfig eth0 192.168.1.1” (where eth0 represents the local NIC device, 192.168 .1.1 is assumed to be the default IP address of the ADSL device). After confirming that the above setting operation is successful, we execute the string command “service network restart” to restart the network connection interface. I believe that the default IP address of the ADSL device and the PPPOE connection interface can be successfully Local NIC devices are bundled together.

If the binding operation is successful, we still can't dial the Internet. Then you can try to ping a specific host IP address in the external network under the command line. If you can't ping the IP of a specific host. Address, it is very likely that the DNS parameters of the local workstation are not set correctly. At this point, we may open the “/etc/resolv.conf” file, find the “nameserver” setting options, and then switch to other options in the corresponding options. The DNS server address that can be accessed normally.

After modifying the DNS server address parameters, if we still can't ping the specific host IP address in the external network, then we can execute the "route -n" syntax command to check the local workstation. If the default gateway parameters are set correctly, if you find that the gateway parameters of the local workstation are set incorrectly, you can try to use the “netconfig” command to adjust the default gateway address parameters.

After the above adjustments, we can now ping the IP address of a specific host on the external network, but if we can't open the specific website content, then we have to do the following checks: Br>

First check if the security level of the firewall is set too high, because during the process of installing the Linux system, the system will often promptly pop up the prompt, we need to set the firewall security level of the system, if we randomly place the local workstation If the firewall level is set too high, it is very likely that the website page will not be opened in the future. At this time, we only need to find a way to lower the firewall security level of the local workstation by one level.

When reducing the security level of the firewall, we can execute the “setup”,“Firewall configuration” command in the command line of the Linux environment. In the pop-up firewall configuration interface, click “Tab” in the keyboard. ; function key, to choose a suitable security level, and finally select “OK” option to save and exit the firewall parameter configuration interface.

If we use the charging Internet access method when applying for ADSL dial-up, then we need to delete the default gateway of the local network card in time, because all information traffic will be automatically in the charging Internet mode. The sending network specifies the gateway.

When deleting the gateway of the local NIC, we can open the file ", /etc/sysconfig/network", then the file, “/etc/sysconfig/network-scipts/ifcfg-eth0” file, and then the corresponding In the file editing window, find the <quo;GateWay” setting option, and then add the “#” symbol in front of the line corresponding to the setting option, and finally save the corresponding file again.

I believe that after the above gradual troubleshooting, we will be able to successfully complete the ADSL dial-up Internet mission!