Knowledgebase
DHCP
Posted by George Chu on 10 April 2013 08:11 PM

DHCP

Contents

Troubleshooting

A DHCP ticket should be opened when the customer's connecting device (computer, router or other device) is unable to obtain an IP address from the carrier's DHCP server.

Install Completed by Carrier Technician

Why?
If the customer never saw a technician it's possible the installation itself was not completed and this would be the source of the issue.

How?
Check with the customer if they saw a technician at any point.

Customer is isolated PC to Modem

Why?
To accurately troubleshoot a DHCP issue we need to isolate the computer directly to the modem as otherwise the router could be the source of the issue.

How?
Walk the customer through bypassing any equipment that might be connected between their computer and the modem.

1 minute Powercycle

Why?
If the customer's equipment is still tied to a certain address in the carrier's servers, it's possible the server will refuse to assign a new address. A long powercycle will generally force the server to release the previous address and assign a new one.

How?
Have the customer unplug the power from the modem and leave it out for 1 minute.

Swapped Ethernet Cable

Why?
A faulty Ethernet cable can cause transmission errors and all kinds of other problems, which could be preventing the customer's computer from obtaining an IP address.

How?
Have the customer find another Ethernet cable to swap out the one between the modem and the computer.

Tried different PC

Why?
Some issues can be caused by an incorrect configuration or software on the customer's computer, to eliminate this, try connecting a second computer.

How?
Have the customer connect a different computer to the modem, in most circumstances you can also use a console (Xbox360 or PS3) to the same effect.

IP Address /when COAX removed

Why?
The IP address that is received with the coax cable unscrewed and set aside from the cable modem is 192.168.100.10 or 192.168.100.11 . If the ip address is different then it can indicate other problems. If a 169.254.x.x ip address is still received at the computer, it can indicate a computer / network card issues. If the customer has a 192.168.x.x address without 100 as the third block it can indicate other equipment connected in between computer and modem.

How?
Attempt resetting the network interfaces at the computer and restarting the computer. Disconnect any equipment in between customer computer and modem and connect them directly for troubleshooting purposes.

Confirmed that the modem is NOT in standby mode

Why?
If the modem is in standby mode, the service will not work.

How?
Ask the customer to verify if the "Standby" light on the modem is solid. For RCA Thomson 425 modem ask the customer which lights are on, if only the "PC Link" and "Cable Link" lights are solid, this modem is in standby.

Attempted Modem factory reset

Why?
This step is requested by the carrier in order to open a repair ticket. Often it will release and renew all the information located in the modem and make the service work better.

How?
Have the customer put the modem on Standby mode and login to the interface http://192.168.100.1

Results of computer in Safe Mode with networking

Why?
This will remove background programs from operating. de-activate firewalls, anti-virus and other interfering 3rd party software to test the connection and see if it is still slow. The steps below may also be completed in this mode to see if problem also exists.

How?
Start computer in Safe Mode with networking support, F8 (Windows only) - Ask customer to reboot computer and press F8 at repeated intervals until black screen showing safe mode options is display. Have customer use arrow keys on keyboard highlight "Safe mode with networking support" and hit Enter.

In Mac OS, while computer is rebooting ask customer to hold the shift key on the keyboard until the dark gray Mac Apple symbol shows on the boot screen. It will take a bit of time to load up (diagnostic checks), at the login screen above the username in red "Safe Mode" will be shown. Customer then logs in.

Computer Information

How?
Open up the command prompt by clicking on "Start" and then "Run" (on Windows XP) or just typing in the start search box (Windows Vista or 7) "cmd". Once the black command prompt window is open, in the field, type "ipconfig /all".

IP Address

Why?
If the customer is actually experiencing a DHCP issue, they should be receiving a 169.254.x.x IP address, if they are receiving anything else, it is not a DHCP issue.

Default Gateway

There should be no value for this field if the customer is having a DHCP issue.

DNS

This value will generally not be present for DHCP issues.

NIC Mac Address

Why?
The carrier wants this information so they can determine which device is trying to obtain an IP address through the modem and see if this information may be trapped in the servers on their end.

Operating System

Why?
This information generally does not matter but Rogers claims certain operating systems cause issues. It's always a good idea to track this information for future reference.

Ping 127.0.0.1

Why?
This test confirms if the customer's network card and other interfaces are working properly as it sends a ping request from the computer to itself, if this test fails, the customer's computer is more than likely the cause of the issue and it should not be escalated.

How?
Ask the customer to go to "Run" and type in CMD, then enter. Once there, type in "ping 127.0.0.1". Ask the customer for the "Average" value under the "Round Trip Time"

Tracert to www.google.ca

Why?
The tracert command is used to visually see a network packet being sent and received and the amount of hops required for that packet to get to its destination.

How?
Ask the customer to go to "Run" and type in CMD, then enter. Once there, type "tracert google.ca". Ask the customer for their results.

Required Information

Modem Light Status

Whenever you are escalating an issue for cable, always include the light status for the modem. This light status can confirm the issue or indicate what the issue is. Refer to the appropriate light status guide: Motorola SB510X or DCM425.

Motorola SB510X

Power:

Receive:

Send:

Online:

PC/Act:

Standby:

RCA Thomson DCM425

Internet:

PC Link:

Cable Link:

Cable Activity:

Message:

 

Modem Information

Always gather this information directly from the customer's modem and confirm it with what is active in the portal and their DAS account.

MAKE & MODEL:

HFC MAC:

CUST SERIAL:

 

Availability / Contact Info

Always get the customer's contact information, especially in cases where they have a bundle as the home phone number will not work. Also keep in mind some providers (Shaw) want 3 possible dispatch dates and times, append that information to these tickets.

Primary Contact Number:

Secondary Contact Number:

Preferred Time for Contact:

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