# Comcast Cable Internet Problem!?!



## blakeas (Jul 12, 2005)

I recently switched from Earthlink DSL to Comcast cable internet service - Well my first 2 weeks is any indication - I cant wait to go back! I have a D-Link NC-202 modem and a Dlink DI-624 wireless router - I have a desktop and two laptops. I was having problems getting on to the internet. I could get to the internet for 2 minutes and then the next 20 minutes I would not be able to connect. However all the lights on my cable modem were what they were suppossed to. I called tech support and they said they could see my modem but they could not receive a signal from me after we did all the tests of unplugging, rebooting, etc. They said it was something wrong with my computer setup - But I cannot see that being the case because I NEVER had a problem with DSL running on my computer with my setup. What can I do? Help!


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## JamesO (Mar 30, 2005)

I assume you meant the model of the cable modem was a DCM-202??

Look at this link:

http://support.dlink.com/products/view.asp?productid=DCM-202

It appears there is a modem firmware for Comcast users only!! Maybe something you need to look into.

Additionally, can you tell us about the router configuration??

Have you had to reset any equipment to get the connection back working?

Do you have DHCP enabled on the router?

Do you have any static IP addresses in any of your computers?

Are you using WEP on your wireless portion of your router?

Do you loose Internet connection to all computers?

Have you looked at the cable modem signal stats? Can you tell us wha the signal levels are and what the S/N value is? Open your web browser and enter this IP address 192.168.100.1, you may need to connect a machine directly to the modem to get the modem web interface open.

Do you know how to use the "ping" and "ipconfig /all" commands?

JamesO


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## johnwill (Sep 26, 2002)

I'd press them to make a house call, they can test on the interface side of the modem and make sure it's not their equipment. That's what you pay for, might as well get it.


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## blakeas (Jul 12, 2005)

How do i check the firmware of my modem?


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## JamesO (Mar 30, 2005)

Open your web browser and enter this IP address 192.168.100.1, you may need to connect a machine directly to the modem to get the modem web interface open.

Probably on the status tab??

JamesO


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## johnwill (Sep 26, 2002)

I actually don't think you should have to worry about the firmware of the modem. If it's a Comcast modem, it's their problem to get it working.


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## BMR777 (Apr 27, 2005)

I am finding that the same thing happens to me on Comcast. I can IPConfig and get an IP address, but no Google comes up in IE. :dead: The lights are all on like you said. I am using the older Comcast Motorola Surfboard Modem. I find that I can fix this either by unplugging the modem power and let it sit for 2 - 3 minutes, or by taking the cable from the modem to the PC, yank it out, lose the connection, plug it in, and let Windows reconnect. Some times I have to do this 2 or 3 times to get it to work but it comes back. :sayyes: 

No matter what Comcast says, we all know it's their fault! :sayyes: 


Hope it helps,
BMR777


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## blakeas (Jul 12, 2005)

OK - I will take out my wireless router and then check the firmware of the modem.......


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## JamesO (Mar 30, 2005)

I assume the D-Link modem was not Comcast supplied?? 

Is the D-Link a "Comcast" approved cable modem?

As for problems with your web surfing, might be a DNS issue, maybe you should manually add one Comcast DNS server and one non Comcast DNS server and see what happens!

JamesO


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## johnwill (Sep 26, 2002)

FWIW, I have a Toshiba modem that I own. When I had a problem a few months back, Comcast came out and did all the standard troubleshooting, and even loaned me a modem for a few weeks while I sent mine back for warranty repair. They're in the business of selling broadband, and an unhappy customer isn't a good advertisement. :smile:


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## JamesO (Mar 30, 2005)

Comcast sure is more customer focused than Cox.

Cox provided a free cable modem as part of signing up for service, modem died under 1 year manufacturer warranty period. Cox claims they only address problems for first 30 days. Cox response was to contact the modem vendor or you can rent one from us!!

JamesO


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## JamesO (Mar 30, 2005)

Here is the approved cable modem list for Comcast:

http://www.comcast.com/Support/Corp1/FAQ/FaqDetail_2427.html

Quote regarding the D-Link DCM202

"If this modem is purchased at a retail outlet (such as Best Buy) please be sure that the box is clearly labeled "Comcast Certified". If it is not, please visit the in store help desk to ensure the correct firmware is loaded to the modem."

I assume D-Link is not supplied by Comcast? 

JamesO


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## blakeas (Jul 12, 2005)

Well - I wanted to give an update - The tech from Comcast came out yesterday and tested at the box, At the split box in my laundry room and then at the back of the modem and he did not find any problems. He did not test my firmware though. My internet has been up and running for 4 days now so I dont get it. He said something that the cable from my box to the source might be the problem - But he said i should be ok - It seemed like this happenned during storms so I asked him If he can insulate the outside box and he said no he cannot. So I am out of ideas.


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## blakeas (Jul 12, 2005)

When i open up the browser and type in 192.168.100.1 - The box comes up for the DCM-202 but What should i put in for user name and password?


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## JamesO (Mar 30, 2005)

Where did you get the D-Link DCM-202 cable modem?

Comcast, purchase locally or mail order/on-line?

This might be important as to the firmware level that is currently in the modem.

Chances are if it was not provided by Comcast, you will need the Comcast specific firmware, version 2.0.1.

I would highly advise you look at the manual and/or the D-Link web site as this info is all available!

http://support.dlink.com/faq/view.asp?prod_id=859&question=DCM-100 / DCM-200 / DCM-201 / DCM-202

JamesO


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## JamesO (Mar 30, 2005)

Could you also post the information on the router configuration as I had previously requested?

Who set up the router?
Did you have the same router when using the DSL service?
If this router was used for the DSL service, has it been reconfigured?
Is PPP/PPPoE still configured?

I see there is one other Comcast user who responded within this post with a similiar problem! I am also starting to think that Comcast may be having some DNS issues, so adding a non Comcast DNS server might be useful? 199.166.31.3 has been useful for me in the past!

JamesO


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## blakeas (Jul 12, 2005)

I signed up with comcast through this comcast special offers website and they partnered with broadband national and that is where i got the modem.


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## JamesO (Mar 30, 2005)

I would start by checking the firmware. Who knows if the equipment supplier made sure if the D-Link had the correct firmware?

JamesO


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## blakeas (Jul 12, 2005)

thanks - I went in and it says my software version is 2.00.03D1.02 - Is that the firmware?

And I setup the DI-624 for the dynamic IP address - which is for cable internet service and I had PPOE for DSL so I did change it.

I also have WEP encryption enabled on my router for 64BIT. And it is what i Had with my DSL so no change there. Thank you for the login instructions - I should have looked that up.

And this is my event log from that web page utility for my modem:

System Event Log
Index Date/Time ID Level Text 
1994 07/12/05 07:09:19 R05.0 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out 
1995 07/12/05 07:09:21 R06.0 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted 
1996 07/12/05 07:09:21 U02.0 critical UCD invalid or channel unusable 
1997 07/12/05 07:09:21 T01.0 critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing 
1998 07/12/05 07:09:21 T04.0 critical SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period 
1999 07/12/05 07:09:38 R02.0 critical No Ranging Response received - T3 time-out 
2000 07/12/05 07:10:10 R05.0 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out 
2001 07/12/05 07:10:12 R06.0 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted 
2002 07/12/05 07:10:57 R02.0 critical No Ranging Response received - T3 time-out 
2003 07/12/05 07:10:58 R03.0 critical Ranging Requests Retries exhausted 
2004 07/12/05 07:11:20 D01.0 critical DHCP FAILED - Discover sent, no offer received 
2005 07/12/05 07:11:21 T01.0 critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing 
2006 07/12/05 07:11:39 R02.0 critical No Ranging Response received - T3 time-out 
2007 07/12/05 07:12:12 R05.0 critical Started Unicast Maintenance Ranging - No Response received - T3 time-out 
2008 07/12/05 07:12:14 R06.0 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted 
2009 07/12/05 07:12:58 R02.0 critical No Ranging Response received - T3 time-out 
2010 07/12/05 07:12:59 R03.0 critical Ranging Requests Retries exhausted 
2011 07/12/05 07:13:23 D01.0 critical DHCP FAILED - Discover sent, no offer received 
2012 07/12/05 07:13:23 T01.0 critical SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing 
2013 07/14/05 22:46:18 R02.0 critical No Ranging Response received - T3 time-out


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## blakeas (Jul 12, 2005)

Where and How do i add a non comcast DNS server?


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## JamesO (Mar 30, 2005)

Based upon the log info, it appears that you are having a basic problem with communication between the cable modem and the cable headend equipment?

I do not know this modem, however, there should be a signal status page. What does the modem show for signal levels and Signal to Noise value?

As for the software/firmware version, it appears you may need to update this?? If should be fairly clear, I would suggest you read the manual or contact D-Link for more details. I am assuming the Comcast specific firmware would have Comcast name or logo show up somewhere on the web interface?? 

Until you can verify you have the correct firmware, I would not spend a lot of time with the modem communication issues, but the signal levels would be useful at this point.

As for the non Comcast DNS server, I would start by putting this on only a single PC so you can determine if DNS is a problem. It can be entered manually under Control Panel, Network Connections, Internet Protocol (TCP/IP), Properties.

JamesO


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## blakeas (Jul 12, 2005)

Downstream Signal
Favorite Downstream Frequency: Hz 
Frequency: 687000000 Hz 
QAM Mode: 256 QAM 
Channel Power: -10.1 dBmV 
SNR: 31.210 dB 


Upstream Signal
Channel Id: 4 
Frequency: 30992000 Hz 
Channel Width: 3200000 Hz 
Channel Power: 36.5 dBmV 


DOCSIS1.0 Class of Service Parameters
Class ID 2 
Max Downstream Rate (bps) 4400000 
Max Upstream Rate (bps) 384000 
Upstream Channel Priority 1 
Guaranteed Min Upstream Data Rate (bps) 0 
Max Upstream Transmit Burst (bytes) 0 
Privacy Enable 1


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## JamesO (Mar 30, 2005)

Levels look acceptable. 

Downstream level a bit on the lower side, most modems allow for -15 dBmV.
SNR at 31.21 is close to the edge for 256 QAM, usually like to see it around 33 dB for 256 QAM.

If Comcast can keep solid levels, this should not be an issue. If your modem has a solid lock light and you cannot browse, then most likely it is not signal related.

Verify the firmware issue on the modem, this is important!

JamesO


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## blakeas (Jul 12, 2005)

Well I updated the firmware on my modem and that seemed to help my stability - But I am still having that problem with Yahoo not coming up. I clear the cookies and temporary files. And that seems to fix the problem...for while...and then it comes back again a few hours later. I though I had a virus but I did the trend-Micro free virus scan. And It did not find anything. What could it be?


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## JamesO (Mar 30, 2005)

Cache problem with ISP or DNS would be my guess. 

Also try to ping www.yahoo.com and see what happens.

Add a manual DNS entry and see if it helps.

One alternate DNS server is use is 199.166.31.3

JamesO


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## blakeas (Jul 12, 2005)

How do i do that?

Here are my settings from my modem webpage - Are they normal still?

Downstream Signal
Default Downstream Frequency: Hz 
Frequency: 687000000 Hz 
QAM Mode: 256 QAM 
Channel Power: -4.2 dBmV 
SNR: 32.288 dB 


Upstream Signal
Channel Id: 4 
Frequency: 30992000 Hz 
Channel Width: 3200000 Hz 
Channel Power: 29.8 dBmV 


DOCSIS1.0 Class of Service Parameters
Class ID 2 
Max Downstream Rate (bps) 6600000 
Max Upstream Rate (bps) 384000 
Upstream Channel Priority 1 
Guaranteed Min Upstream Data Rate (bps) 0 
Max Upstream Transmit Burst (bytes) 0 
Privacy Enable 1


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## karly (Oct 18, 2005)

hi. i didnt read the whole conversation but i did see that your having a bloc sync no surf problem. i would agree that it is potentially a DNS problem. I also saw that you were having trouble with the router, i'll try and offer suggest for both things
1st DNS: best test for DNS that is to PING and then try surf. "ping google.com" & "ping 216.239.37.99" (that is the IP for google, or use 216.239.57.99). if you get replies from both or both timeout then it isnt dns. if you get results from the IP but not the name, then take the IP into your browser and see if you get to google or not. If you can, then its definate dns problem. if not, then other stuff
2nd router: I am not well versed on routers, but i did see that you used to have DSL and now have Cable internet, there are router configurations for both, you may need to reset the router back to defaults and start over.


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