Troubleshooting of Linux Network ADSL connections

Article Title: troubleshooting of ADSL connections in Linux Networks. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

First check if PPPOE software is installed and the version is higher than 3.5-1. if the version is earlier than this version, upgrade the software version (the latest rp-ppoe-3.5-3.i386.rpm) first ). Upgrade command: # rpm Uvh rp-ppoe-3.5-3.i386.rpm ADSL device is usually through the ethernet card to dial, establish a PPP link, at this time the PPP protocol is called PPPoE, that is, ppp over Etherent (on the Ethernet point-to-point communication protocol ). Generally, you do not need an ADSL Modem driver. You only need to establish a PPPoE connection. If the connection fails, follow these steps: 1. Run the ifconfig-a command to check whether the network interface is started and whether the IP address is bound to the NIC. If the network interface (PPP0) is not started, run the command ifup PPP0. If no IP address is bound to the NIC (eth0), run the command ifconfig eth0 192.168.1.1 and then run the command to restart the network: service network restart 2. if the network interface and IP address have been bound to the network adapter but cannot access the Internet, run the command: ping a valid external IP address. If the IP address cannot be pinged, the DNS server address is not set. Modify the nameserver address in the/etc/resolv. conf file and change it to a usable DNS server address.

3. If no problem persists, you can run the route-n command to check whether the default gateway is set correctly. You can use netconfig to change the default gateway.

4. if you can ping an external IP address but cannot browse the Web page, there are two common reasons: Firewall reasons: we know that when installing some Linux releases, the system will always allow you to set the firewall level, in some cases, we usually set the firewall level too high. This will happen. In this case, you only need to reduce the firewall level. Method: Run "Setup"-"Firewall configuretion" on the command line and press "Tab" to select the Firewall level. Add * (use space key) before the option ), select "OK" to exit.

Gateway reason: for ADSL users (non-fixed access to the Internet) who use the note to access the Internet also need to delete the gateway of the eth0 Nic, because the network traffic is sent to the gateway at this time, the method is in the file: /etc/sysconfig/network,/etc/sysconfig/network-scipts/ifcfg-eth0, add the symbol before the line of GATEWAY = xxxxx :#.