Troubleshooting of ADSL connections in Linux Networks

First, check whether the PPPOE software is installed and the version is later than 3.5-1. If the version is earlier than this version, upgrade the software version to the latest rp-ppoe-3.5-3.i386.rpm ). Upgrade command: # rpm Uvh rp-ppoe-3.5-3.i386.rpm

ADSL devices usually use Ethernet cards to dial up and establish PPP connections. In this case, the PPP protocol is called PPPoE, that is, the point-to-point communication protocol of ppp over Etherent OVER Ethernet ). 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 following command:

Ifup PPP0

If no IP address is bound to eth0, run the following command:

Ifconfig eth0 192.168.1.1

Run the following 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 webpage, there are two reasons:

Firewall reason: we know that when installing some Linux Release versions, 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 the * Space key before the option ), select "OK" to exit.

Gateway reason: for non-fixed access to the Internet by ADSL users who use the timer to access the Internet, the gateway of the eth0 Nic should also be deleted, 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 :#.