Cable modem keeps losing connection

[zodiac88]

A couple days ago I started having trouble with my cable internet. I have Comcast high speed and a Scientific Atlanta DPX2100 modem. I'm also using a D-Link DWR-2310 router. A couple days ago my internet just stopped working. I didn't get a disconnected popup or anything, the internet just wouldn't work. Now this is common, it happens occasionally and is easily fixed by resetting the modem and router.

So I do that and it's fixed, then a few hours later the same thing happens. Now this has been happening constantly over the past few days. I'm forced to reset my modem about every hour. I've tried various things and I think I narrowed the cause down to the modem. So I'm gonna have Comcast come look at it soon.

I'm pretty sure it's the modem. I've tried other things. I don't think it's software related because the other PC in my network and my Xbox and my PSP all stop working when this happens. I also don't think it's the router. I re-installed the router, updated it's firmware, re-installed it again, and the problem is still happening. So I don't think it's the router or software. I found out that I don't have to reset my router to get the net working again, I just have to reset the modem.

If it helps, here are the logs from my modem: (for some reason the dates are messed up)

Time Not Established critical DHCP WARNING - Non-critical field invalid in response.
TUE JUL 26 20:02:51 2005 critical No UCD's Received - Timeout
TUE JUL 26 20:23:46 2005 critical TFTP Failed - OUT OF ORDER packets
TUE JUL 26 19:48:33 2005 critical DHCP FAILED - Request sent, No response
TUE JUN 14 18:41:51 2005 critical REG RSP not received
SAT MAY 19 17:09:40 2007 critical Received Response to Broadcast Maintenance Request, But no Un...
SUN SEP 11 09:13:23 2005 critical Started Unicast Maintenance Ranging - No Response received - ...
SAT MAY 19 17:09:21 2007 critical SYNC Timing Synchronization failure - Loss of Sync
Time Not Established critical SYNC Timing Synchronization failure - Failed to receive MAC S...
Time Not Established critical DHCP FAILED - Discover sent, no offer received
TUE JUL 26 20:20:56 2005 critical Init RANGING Critical Ranging Request Retries exhausted
Time Not Established critical No Ranging Response received - T3 time-out
SAT MAY 19 17:10:46 2007 critical SYNC Timing Synchronization failure - Failed to acquire QAM/Q...
Time Not Established critical SYNC Timing Synchronization failure - Failed to acquire FEC f...


Here's my modems status:

Cable Modem Status operational
Cable Modem IP Address 73.248.95.188
Current Time FRI NOV 09 00:43:51 2007
Time Since Last Reset 0 days 00h:08m:14s
Configuration File d11_m_dpx2100_silverpboost_c01.cm
Cable Modem Certificate Installed
Connected to MAC Address
Ethernet Port 00:19:5b:4c:b2:62


Here's my signal:

Downstream Status Operational
Channel ID 39
Downstream Frequency 549000000 Hz
Modulation ???
Bit Rate 42884296 bps
Power Level -1.9 dBmV
Signal to Noise Ratio 35.8 dB
Upstream Status Operational
Channel ID 2
Upstream Frequency 22000000 Hz
Bit Rate 10240000 bps
Power Level 39.25 dBmV

Basic info about my modem:

Name WebSTAR DPX2100 Series Cable Modem
Cable Modem Serial Number 101753113
Cable Modem MAC Address 00:0a:73:61:87:f1
Hardware Version 1.1
Software Version 2.0.1r1131-0304
Receive Power Level -1.9 dBmV
Transmit Power Level 39.25 dBmV
Cable Modem Status operational


Any help at all would be appreciated. I'm hoping that it's just a simple problem with my modem or cable line that Comcast will fix when I call them tomorrow.

[YeOldeStonecat]

The most common cause I've found of the modem losing touch with the ISP...is a cable splitter going bad..especially common if you have one outside..the outdoor environment can require yearly replacement of it.

That's the first, easiest, and least expensive fix I'd try.

[biggdogg40509]

i think i have been having symptoms similar to the OP. on my home network i have 2 pcs and 2 xbox 360s, all wired to a linksys befsr41. and all had been fine up until about 2 weeks or so ago when i would notice that my main pc would lose connection at any given time. the 2nd one and the 360s don't have problems, and it isn't an IP address conflict.
i just can't seem to figure what could cause the one machine to drop connection for no reason.

[Mastershake503]

I'm having the same problem i have a gaming computer and i do a lot of well gaming i also have comcast and i have had no problem befor and i have done alot to try to solve this problem 1st i called comcast and had them come to my house they told me it was fine and i thoght it was AT 1st 14 15 hours later it lost connectivety so i called them told them i was using a linsys router and that i was getting "limmeted to no connectivety" they told me i needed to use "port forwading" i said ok so i set up port forwading and nothing changed so i was mad and comcast wwas not going to do any thing for me so i grabed my modem and my router and houlked it all up worked fine once agian for 3-4 hours told comcast and the lady on the phone did the hole restart from the offec told me my modem was not pluged in but infact it was all the lights were lit up the modem its self looked like it was working fine tryed it with the router with out the router with no change then i was going to cal comcast one more time and if they didnt fix it i was going to get qwest well i called they told me i was running it to hard that the BUFFERS WERE getting overloaded and that is why it would do that they told me i needed to come in and get the modem replaced beacuse it was going to keep doing that my modem like yours is about 1-2 years old




SO WHAT IM TRYING TO SAY IS ITS NOT THE ROUTER OR THE WAY YOU HAVE ANYTHING CONNECTED IT IS THE SIMPLE FACT THAT THE BUFFERS ARE GETTING OVER RAN SO GO TO COMCAST AND GET A NEW MODEM THAT IS WHAT WORKED FOR ME !!!!!!

[Mastershake503]

O AND THEY ALSO JUST SWICHED EVERYTHING TO HIGH SPEEDS OR SOMETHING LIKE THAT THEY TOLD EVERY ONE FROM COMCAST TO POWER CICKLY THERE MODEMS
I THINK THAT HAS SOMETHING TO DO WITH IT SORRY FOR THE SPELLING I HAVE LIKE 4 MIN BEFOR WORK ANY I HAD TO TYPE FAST

E MAIL ME IF YOU NEED TO KNOW ANYTHING ELSE wannaseemycatpoop@hotmail.com

[mccoffee]

another reason could be an ethernet cable is going bad it happen to me once