Cable Internet problems

I've been having problems with my cable internet lately where it'll work fine for a day or so and then without me changing anything I won't be able access the internet and then it'll start working again ... I'm 99% sure that it has nothing to do with my config. Ths cable company assures me that there isn't any work going on in the area but it seems to be happening during the day. The question being is there a simple tool software/hardware to test signal from your cable provider? So at least I can isolate it to them? When the cable dude came he attached a machine which tested the voltage I think?
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The thing cable dude brought with him was a signal strength meter.

Besides that - probably cables are not the one to blame but the ISP - they are not the same entity all the times (I am not sure its ur case, but anyway).

What type of the connection do u have? VPN (dialer) or an MPLS (DHCP client  like in regular lan)?
Sometimes although the signal is OK - the connection is dropped and in order to renew it DHCP client requests for an IP again and it does this periodically. So in case the connection was dropped and until Windows will renew automatically the IP address - Internet won't work. What you need to do is this:

1. Check the modem leds - in case they are all OK then modem is synchronised and the cable connection is fine.
2. Open CMD (Start->Run-cmd) and type "ipconfig /release" and then "ipconfig /renew"

This should help this problem - in case you were able to renew IP address - problem solved., else there is a problem on the iSP side.

NOTE: IP address 169.254.x.x is not a valid for connection - its given by WIndows in case DHCP request failed.

Good Luck.
Are you positive that there is no spyware or viruses on your machine?  Someone could be using it to send out spam, or your there maybe a browser hijacker.  If you are sitting on the internet all day and night without a firewall and/or router you have something on your computer.  If you have antivirus software scan the computer.  Make sure that your virus definitions are up to date.  

Another thing that you can download is Ad-Aware SE.  Go to and do a search for Ad-Aware.  Update the definitions for this as well, and then do a full system scan.  

You can test your bandwidth at to see if you are getting the amount that your ISP is advertising or saying that you should get.  I hope that this helps.

Good Luck,

I used to have the same problem with Time Warner Cable... it took 3 different techs to find the two problems.  First, one of the splitters (to TV, to Cable Modem) was not terminated correctly and the dude discovered and fixed that.  This did not resolve the problems however.  Second dude was from their BT (building trouble?) group.  He's the one who checked the signal from the basement of the building and found nothing wrong. Finally, a third tech-dude discovered another splitter in the other room that was reversed.  Compounding the problems, there was constructions in the streets (as is always the case in New York City) and real outages were frequent and tech support did not know about them!?

Does that sound similar to your problems?

P.S.  My cable connection has been stable for about a year now and I rarely loose it.  A line-interactive UPS is protecting my router and cable modem too so that probably helps my case.
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stefanomarcoAuthor Commented:
Hi plemieux72 that does sound like a very similar problem ... what's really annoying now though is that the techo is coming around in an hour and it's working perfectly!! I'm going to look like a complete goose. I suppose the thing I need to be able to do is to show that the problem originated from there side ... ps everything is up to date ie virus/spyware/xpsp2 etc
some tests to run when it is down
as mantioned above
from a prompt type
ipconfig /all
and see if you have a valid ip address
also from the prompt
and then from the prompt type
check the results (you may want to run these tests while it is working to give you a baseline)
there should be a space in that ping command
You could have the cable company check the line and ensure the data frequency ranges are correct and that your cable modem is able to lock onto a signal.  Sometimes thunderstorms can affect the line, such that the data stream frequency gets mesed up.  

When you internet goes out, what exactly happens.  Does your system lose it's IP address, and/or does your cable modem's cable/link light remain illuminated?  Can you describe more about what specifically happens to your modem?
One more thing, one time a neighbor decided to illegally hook up his cable.  His modification caused my cable to intermittently work because there wasn't enough signal on the line.
stefanomarcoAuthor Commented:
how's this for classic ... techo came not a problem ... just after he left ... problem!! :(
so ... i'm using dial up on this computer and I've connected my laptop directcly to the cable modem using their dial in software ... to elimiinate there being a problem with my router ...
i'm getting an ip on the laptop but no pages coming up ... if i try to ping anything it just times out ... aahh! ;)
Try this at a command prompt:


Does it return an IP address of

If it doesn't, you have a DNS name resolution problem and we can help you fix that.  Otherwise, we'll keep troubleshooting...
This is a common problem and most likely has to do with the signal strength of your signal at the datacenter, not the datacenter's signal strength from your point of view.

You probably have splitters between where the cable signal comes in and where your cable modem is.  You may even have a signal booster.  Change the splitter configuration so that there is a two-way splitter right after the signal comes into your house.  Run one side to your cable modem, and run the other side to other splitters that supply your TVs.

Each splitter the signal has to pass through on its way from the cable company to your modem reduces the signal level by about 6db, and you are probably borderline on your signal level.

There is one other possibility: check to make sure all of your cable connections are properly waterproofed.  Water seeping into the connection can also screw things up.  You'd probably know if this was the case though: you'd lose your internet about an hour after it started raining.

Hope this helps!


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stefanomarcoAuthor Commented:
Thanks for the input :)
One last comment I forgot to mention: Cable modems work at higher frequencies than normal TV signals.  Make sure your splitter is one of the kind that includes frequencies all the way to 1GHz.

Sometimes cable technicians will only check the signal strength of the TV signal instead of the signal strength of the Cable modem signals. This is a problem because cable modem signals attenuate faster in the cable line since they are higher in frequency.  Thus, sometimes your cable repair guy will say, "well the signal is just fine," when in reality it's way too low.

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