Use commands to troubleshoot ADSL dial-up failures in Linux

I believe most of my friends are using ADSL dial-up Internet access in Windows. If a dial-up Internet access failure occurs in this environment, you only need to search the Internet based on the fault, you can easily find a solution to the fault. However, some friends often need to perform ADSL dial-up Internet access in a Linux environment to meet their work needs. When a fault occurs in this dial-up environment, I believe most people will be unable to cope. In fact, we still have rules to follow when troubleshooting the ADSL dialing fault in Linux. This is not the case. When we encounter an ADSL dial-up Internet access failure in Linux, we can try the following methods to troubleshoot the problem one by one. I believe the problem will be solved quickly and effectively!

In the case of an ADSL dial-up failure, the first thing we need to do is to promptly upgrade the PPPOE dial-up program so that it can work in the latest version, the speed and stability of ADSL dial-up Internet access are guaranteed.

In general, the PPPOE dial-up program version in Linux should be higher than 3.5-1. If we find that the current version of the dial-up program is earlier than this version, we can download the latest version of PPPOE dialup program online, assuming the new version of PPPOE dialup program named rp-ppoe-3.5-3.i386.rpm, then we can execute the string command "rpm Uvh rp-ppoe-3.5-3.i386.rpm" in the command line in the Linux environment, so that the PPPOE dialup program in the Linux environment can be upgraded to the latest version.

Considering that ADSL devices are often directly connected to network card devices, we often create a point-to-point communication link over Ethernet through the PPPOE dialing program before direct dial-up, this is a common PPP link. Therefore, when we confirm that the PPPOE dial-up program is in the latest version, if the ADSL dial-up Internet connection still fails, we should carefully check whether the PPP link is normal.

When checking whether the PPP link is normal, run the "ifconfig-a" string command in the command line of the Linux environment, using this command, we can find out whether the network connection interface of the local workstation is in the starting status, and whether the local Nic is bound with a suitable IP address. If the PPPOE connection interface of the local workstation is not started, run the "ifup PPP0" string command to restart the PPP0 network interface of the local workstation.

If the default IP address of the ADSL device is not bound to the NIC device of the local workstation, Run "ifconfig eth0 192.168.1.1". eth0 indicates the local Nic device, 192.168.1.1 is assumed to be the default IP address of the ADSL device ). After confirming that the preceding settings are successful, run the "service network restart" string to restart the network connection interface, we believe that the default IP address of the ADSL device and the PPPOE connection interface can be successfully bound with the local Nic device.

If we still cannot dial the Internet when the binding operation is successful, we can try to Ping a specific host IP address in the Internet under the command line, if the IP address of the specified host cannot be pinged properly, it is likely that the DNS parameter of the local workstation is not set correctly. In this case, open "/etc/resolv. in the conf file, find the "nameserver" setting options, and then replace the corresponding options with other DNS server addresses that can be normally accessed.

After modifying the DNS server address parameters, if we still cannot Ping the IP address of a specific host on the Internet, we can run the "route-n" string command, check whether the default gateway parameters of the local workstation are correctly set. If you find that the gateway parameter settings of the local workstation are incorrect, you can use the "netconfig" command to adjust the default gateway address parameters.

If we can now successfully Ping the IP address of a specific host on the Internet, but cannot open the specific website content, perform the following checks:

First, check whether the security level of the firewall is set too high, because during the installation of the Linux system, the system will usually pop up a prompt asking us to set the firewall security level of the system, if we randomly set the firewall level of the local workstation too high, it is very likely that the website page will not be opened in the future, in this case, we only need to reduce the firewall security level of the local workstation by one.

When reducing the security level of the Firewall, we can execute the "setup" and "Firewall configuration" commands in the command line in the Linux environment, in the pop-up firewall configuration interface, select a suitable security level through the "Tab" function key on the keyboard, and then select the "OK" option to save the exit firewall parameter configuration interface.

If we select the billing method when applying for ADSL dial-up Internet access, we also need to delete the default gateway of the local Nic in time, in the billing method, all information traffic is automatically sent to the specified gateway.

When you delete the gateway for the local Nic, you can open the/etc/sysconfig/network file and the/etc/sysconfig/network-scipts/ifcfg-eth0 file, then, find the "GateWay" setting option in the corresponding file editing window, and add the "#" symbol before the row where the option should be set, finally, save the corresponding file again.

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

1. Description of ADSL dial-up Internet access in Linux
2. ADSL dial-up Internet access enables automatic server and network connection