Troubleshooting guide

Table of Contents
Cisco DSL Router Configuration and Troubleshooting Guide
Troubleshoot Your Configuration..........................................................................................................47
Cisco DSL Router – Acting as a PPPoE Client with a Dynamic IP Address........................................47
Tasks to Perform....................................................................................................................................48
Possible Required Configuration Steps on the PC.................................................................................48
Configuration.........................................................................................................................................49
Troubleshoot Your Configuration..........................................................................................................50
Cisco DSL Router – PC Acting as a PPPoE Client...............................................................................51
Tasks to Perform....................................................................................................................................51
Configuration.........................................................................................................................................51
Troubleshoot Your Configuration..........................................................................................................52
Cisco DSL Router – Acting as a PPPoE Client with a Static IP Address.............................................52
Tasks to Perform....................................................................................................................................52
Possible Required Configuration Steps on the PC.................................................................................53
Configuration.........................................................................................................................................53
Troubleshoot Your Configuration..........................................................................................................55
Step−by−Step Configuration of PPPoE with a Static IP Address.........................................................55
Step−by−Step Configuration.................................................................................................................55
Connect the Cisco DSL Router and Your PC.................................................................................55
Start and Set Up HyperTerminal.....................................................................................................56
Clear Existing Configurations on the Cisco DSL Router................................................................56
Configure the Cisco DSL Router....................................................................................................57
View Your Configuration................................................................................................................59
Configuration.........................................................................................................................................59
Troubleshoot Your Configuration..........................................................................................................60
PPPoE: DSL Router as a PPPoE Client – Troubleshooting..................................................................61
Determine the Layer to Troubleshoot....................................................................................................61
Layer 1 Issues........................................................................................................................................61
Is the carrier detect (CD) light on the front panel of the Cisco DSL Router on or off?..................61
Is your ISP using a DSLAM that supports the Alcatel chipset?.....................................................61
Is the DSL port on the back of the Cisco DSL Router plugged into the DSL wall jack?...............61
Is the ATM interface in an administratively down state?...............................................................62
Is the cable pinout correct?..............................................................................................................62
Do you have the correct power supply for the Cisco 827?.............................................................63
Is the DSL operating−mode correct?..............................................................................................63
Is the circuit tested/provisioned correctly?......................................................................................63
Layer 2 Issues........................................................................................................................................63
Do you have the correct PVC values (VPI/VCI)?...........................................................................63
Are you receiving data from your ISP?...........................................................................................63
Is a PPPoE session up?....................................................................................................................64
Are you receiving a PPPoE response from the aggregation router?...............................................65
Is PPP negotiating properly?...........................................................................................................65
How do I know if my PAP username and password are correct?...................................................69
How do I know if my CHAP username and password are correct?................................................69
How do I know when PPP authentication is successful?................................................................70
Why can I access some web pages with PPPoE but not others?.....................................................71
Additional MTU Troubleshooting Steps.........................................................................................72
Related Information...............................................................................................................................72
Cisco DSL Router Configuration and Troubleshooting Guide
iii