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5.4 Troubleshooting


When requesting help regarding connectivity issues the more information you can provide in these areas the more likely it is somebody will be able to help you:

    •Have you called Charter support at 1-888-GET-CHARTER (438-2427)?

    •The hardware -- What make and model of equipment are you using? Have you power cycled your equipment? If you're having connectivity issues and there is a hub, router, or switch in place, does the problem remain if you bypass any of these devices and connect your cable modem directly to your PC's NIC?

    •Have you made any changes to your hardware configuration recently? If so, please describe.

    •Have you performed a:

    and if so, post the results.

  1. Your software. Are you running a firewall or intrusion detection software and if so, what is it?

  2. Viruses. What, if any, anti-virus software are you running and is it up to date?

  3. Spy-ware. What, if any, antispyware software are you running and is it up to date?

  4. In what City and State are you located?

  5. In your opinion, what is the connectivity problem? (speed issue, loss of sync, dropped packets, other)

  6. Provide any other information that you think will help others help you.


Please, thank you, and other common courtesies are always appreciated!

*Note - If you call a Charter contact center, please do not
request a specific tech from BBR/DSLR, thanks.


by nozero See Profile edited by defiant See Profile
last modified: 2007-10-07 20:13:29

On a number of cable modems you can go to the modem's internal pages to view your power levels, SNR, etc. using http://192.168.100.1/ in your browser. Some modems require additional settings.

by IcEr3K See Profile edited by defiant See Profile
last modified: 2007-10-08 19:33:05

Information on signal levels: http://homepage.ntlworld.com/robin.d.h.walker/cmtips/signal.html

Downstream power level (Receive): -12dbmV to +12dbmV
A value below -12 indicates a poor downstream signal. A tech would aim for a value close to the optimal 0 dBmV, but a good cable modem should be capable of working within the broader range of -15 to +15 dBmV, provided the downstream Signal to Noise Ratio remains good enough.

Upstream (Transmit): +35dbmV to +50dbmV.
A value within the range +35 to +50 dBmV is within spec with 40's the most common.

Carrier/Noise Ratio: greater than 33dB .
The downstream Signal to Noise Ratio must be 30 dB or higher, and should ideally be 33 dB or higher. The lower ratio the more noise and the poorer the performance. The Cable Modem will have to keep requesting retransmissions of packets with uncorrectable errors.

Please visit the following thread for the latest on this issue: »Charter HSI: Acceptable Signal Specifications

by stan999 See Profile edited by defiant See Profile
last modified: 2007-10-08 19:47:04

If you are using a router or software firewall and have the firewall set to block ICMP Echo Request then your first hop will not respond to the ping requests.

by redxii See Profile edited by nozero See Profile
last modified: 2005-09-03 18:41:09

If you have packet loss at your end:

    •Power down your modem for one minute, then back on.

    •Check your signal levels, Make sure they are within specs.

    •Check your cable connections. Make sure they are tight.
    •Place your modem and cables away from your monitor due to possible interference.
    •If you are using multiple splitters, then make sure your modem is on the very first split to your house. Try replacing the splitter or your cabling.
If you are still having packet loss, call Charter tech support.

by redxii See Profile edited by nozero See Profile
last modified: 2005-09-03 18:39:43

Usually, this is caused by not power cycling the modem when attaching a new device to the modem. The cable modem stores the MAC address of the previous device it was communicating with. When switching to a new device, the MAC address has changed, and therefor the cable modem is trying to send information to the wrong device.

To correct this, one must unplug the power to the cable modem, then plug it back in. After the modem shows the proper connectivity lights, then turn on the new device and the internet should work. Sometimes a "factory reset" is required in order to clear the MAC address.

Eastern Division Users

Customers have to perform a factory reset on their modems to make them work when switching devices. This is performed of course by taking a paper clip or such and pressing the pinhole on the back of the modem. (This doesn't apply to com21 comports) If a modem does not have a reset they can either contact charter to have the host cleared or disconnect the coax for 3-4 hours to get it to unassociate itself from the old MAC.

Courtesy of: tech327 See Profile

by bigbeartech See Profile edited by nozero See Profile
last modified: 2005-09-03 18:41:58

Click Start/Run and enter cmd (or command depending upon your OS) and click the OK button. In the dos box (the black box that opens up) type tracert followed by the site you want to tracert to e.g. tracert dslreports.com and press the enter key.

To copy the result, right click in the window and from the pop-up menu click select all and press enter on the keyboard. The contents are now on the clipboard and can be pasted into a post or any application that will accept text. If you do not want the entire contents of the window, you can click mark instead of select all, then click and drag across the portion you want to copy. While the desired content is highlighted, press the enter key. Now the selected text is on the clipboard.

If tracert does not work for you, have a look here.

Another alternative is to Click Start/Run and enter cmd /k tracert dslreports.com. You may substitute whatever site you wish to use in place of dslreports.com. Use the instructions in the paragraph above to copy the result.

by nozero See Profile
last modified: 2006-02-04 11:13:26

Due to the nachia/welchia worm many ISP's are now filtering 92 byte icmp echo requests.

More info.

You can also try using an online tracert like the one here »dnsstuff.com/ (third column, second item) or here »www.lantek.co.uk/tracert1.asp.

by nozero See Profile
last modified: 2005-09-03 18:40:00


  • If you are not using a router, the first hop 10.xx.xx.xx address on a tracert will be your Charter UBR. The 10.xx.xx.xx address is the Charter router's private side address of your Default Gateway.

  • If you tracert through the gateway, the Charter UBR private IP address will reply.

  • If you tracert to your Charter's Default Gateway the UBR's public gateway IP address will reply.

  • If you use a home router, the router's address may or may not show as the first hop depending on the type of router you are using.


The cable modem is just a transparent bridge and will not show on a tracert.
More information here on the tracert first hop address.

»homepage.ntlworld.com/robin.d.h.···ml#ubrip

From Stan Gunn's post here.

by nozero See Profile
last modified: 2005-09-03 18:40:15

DOCSISDIAG is a little command line program that allows you to check the power levels and other information on your cable modem, which can be useful for trouble shooting modem problems.

by Axilla See Profile edited by nozero See Profile
last modified: 2005-09-03 18:39:25

You can find a link to download DOCSISDIAG HERE. There is also some information on how to use the program on that page.

by Axilla See Profile edited by nozero See Profile
last modified: 2005-09-03 18:38:31

Please follow the instructions below to begin troubleshooting your connection.

The following steps will guide you through power-cycling your cable modem:

Shut down your computer.

Unplug the cable modem if you cannot power down the unit with a switch.

Unplug ALL cables from the back of the cable modem:

power cord
coax cable
ethernet line
Note the different plug sizes on the ethernet and phone line if applicable.

Leave the cable modem unplugged for a minimum of three minutes.

Re-attach all the cabling in this order:

coax cable
ethernet line
power cord
When the power is returned to the cable modem, observe the cable modem lights and colors as the unit comes back on-line.

Turn on your computer and test your connection.

--------------------------------------------------------------------------------

I would also suggest this text or link to this article from MS to diagnose and Fix a corupt Winsock and/or TCP/IP issue in Windows XP. I have found this to be very common with spyware causing corruption with LSP's. How to diagnose and repair winsock2 corruption in Window's XP »support.microsoft.com/kb/811259 . Or this simple command.Which reset's the registry key's. netsh int ip reset resetlog.txt ,That command is entered via the command prompt,Start-Run-cmd-OK

by volntn See Profile edited by DaSneaky1D See Profile
last modified: 2011-08-12 22:40:11

An alternative, somewhat automated way to accomplish the following is posted at the bottom of this FAQ.

Ping is generally done from a command prompt. From Windows, click start/run then type in cmd /k ping /? and you'll get this list of the available options.



You can incorporate the options into the command line. For example to ping google.com 100 times, you would click start run and enter:

cmd /k ping google.com /n 100
(then press enter). Your results will start off looking like this:



and when completed will look like this:



To copy this information to clipboard for pasting elsewhere, just right click in the window, and from the pop-up menu click select all, then press enter on the keyboard. The information is now on your clipboard and can be pasted into a text file or post. If you do not want the entire contents of the window, you can click mark instead of select all, then click and drag across the portion you want to copy. While the desired content is highlighted, press the enter key. Now the selected text is on the clipboard.



The paste will look similar to this:

Pinging google.com [216.239.37.99] with 32 bytes of data:

Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=53ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=55ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=53ms TTL=236
Reply from 216.239.37.99: bytes=32 time=53ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=49ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=66ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=81ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=68ms TTL=236
Reply from 216.239.37.99: bytes=32 time=53ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=50ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=51ms TTL=236
Reply from 216.239.37.99: bytes=32 time=52ms TTL=236

Ping statistics for 216.239.37.99:
Packets: Sent = 100, Received = 100, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 49ms, Maximum = 81ms, Average = 51ms

C:\>




As an alternative, you can click Start/Run and enter cmd /k ping charter.net -n 100 and press enter or click OK.

To copy the result, right click in the window and from the pop-up menu click select all and press enter on the keyboard. The contents are now on the clipboard and can be pasted into a post or any application that will accept text. If you do not want the entire contents of the window, you can click mark instead of select all, then click and drag across the portion you want to copy. While the desired content is highlighted, press the enter key. Now the selected text is on the clipboard.

Feedback received on this FAQ entry:
  • very nice .thanks

    2009-11-06 07:40:40



by nozero See Profile
last modified: 2006-01-12 08:21:40

A very comprehensive and multinational listing of several hundred speed test sites exists right here.

/stest?more=1

by nozero See Profile
last modified: 2005-09-03 18:39:07

In Windows 98 click start/run and type in ipconfig /all and press enter.

In Windows 2000 or XP, click start/run and type in cmd /k ipconfig /all and press enter.

For those who don't like the command prompt, a nice way to get this info from a gui is IP2 1.03 available from »www.keir.net/ip2.html.



by nozero See Profile
last modified: 2005-09-03 18:54:44

If you are unable to get to the modem's internal pages via »192.168.100.1, here's a couple of things that may help:

    •If you are connected through a router, you may need to power-cycle it first (unplug the power for approx. 30 seconds, plug it back in, and then try). Also, some modems won't allow a connection to the internals from a computer with a router-class IP address...you may need to connect the modem directly to the PC, power-cycle the modem, and then try again.


    •If the above doesn't apply or if you're still unable after bypassing the router, open the control panel, right click on your local area connection, and click on properties. Highlight (but don't uncheck) Internet Protocol (TCP/IP) and click the properties button. Set your IP Address to be 192.168.1.11 with a subnet mask of 255.255.255.0. You should then be able to access what you need. Just remember to set it back to obtain automatically after your done, otherwise even if the modem does reacquire a connection you won't be able to get online.



Feedback received on this FAQ entry:
  • If using a Scientific Atlanta 2100 / WebSTAR DPC2100R2 you can go to the following page http://192.168.100.1/_aslvl.asp and set it to Access Level 2 with password "W2402" (without quotations). That will allow access to the logs and other details for a short time.

    2010-09-14 11:49:33 (Koitenshin See Profile)



by nozero See Profile
last modified: 2005-09-03 18:37:46


  • Change the device the cable modem is connected to e.g. the NIC, hub, or router.


    or

  • Note when your current DHCP lease expire and disconnect your modem starting a few minutes prior to that time and leave it disconnected for a few hours past the renewal time.


The above is from the Source post by Drew502 See Profile.



I also found these links with other methods at http://www.klcconsulting.net/smac/.


by nozero See Profile
last modified: 2006-01-01 12:42:12