Brief Internet Disconnection Problem/NIC Testing

In the past few days (XP/SP2, no router, no config changes), my internet connection has started behaving strangely. All's running fine, then a sudden disconnect (XP balloon says "connection is unplugged "), then maybe a second (or less) later, all is OK again ( "connected at 100 mbps "). A couple of minutes or hours later, it happens again....and again....and again....very sporadic, extremly brief disconnects. The cable connections are all tight, I've done the "reset modem" bit, but I can't get the disconnects to stop. So is the problem with my cable company (Comcast, and they're mucking around someplace on the network), or is it me/my modem?

I'd like to be sure it's not the NIC card, so I Command Prompt>typed in "ping xx.xx.x.xxx ", where the x's are my IP address. Is this how I ping my NIC ? The results looked normal, no strange messages back to me. Can I now assume the NIC is OK? Ever see a problem like this?

 

Not a normal response when cable company has service problem. If you can substitute a different cable (modem to Nic), then that can be taken out of the mix. You could ask / request a different / substitute modem from com.cast. If problem continues, NIC appears to be failing.

 

Additional checking ....
In front of the cable modem, be sure cable company connections are secure / tight. Do you have a line splitter (one to TV, other to cable modem)? If yes be sure all 3 connections are secure. Checking these cables will not have "Network Connection" influence. If they were not making connection, you would not have internet service.... when you are moving / checking network connections, they may become loose.

 

Dennis....I think you and I are in the same place. I'm sure all the connections are tight, and when the Comcast guy comes next week, I'll ask for a new modem. And if that doesn't work, I guess it's the NIC. I did run a power test on my modem, got Receive Power Level: 0.15 dBmV,
Transmit Power Level: 52.25 dBmV. To me that seems like a big two-way differential, esp the 52....like the modem's working awfully hard to pump data down the line.

 

"Signal" Power Level readings from my modem / diagnostics ...
-3 dBmV = Downstream
49 dBmV = Upstream

Have no idea what these values represent, other than they appear to be very opposite. If I was to guess which device is failing, it would be the NIC. Just don't hear of cable modems failing that often .. but I'm sure they do. Keep us posted when the "Cable Guy" shows up. Good luck.

 

Ping -t 127.0.0.1
is the way to test your NIC. With the -t switch it will run until stopped so let it go through a screen or two of returns and look for any errors, failures, or overlong responses.

If you don't like watching that sort of mess (I don't) or want to let it run longer,
ping -t 127.0.0.1 > c:\ping-test.txt
and you won't see any onscreen results but you'll capture all of them in a text file that you can examine.

Ctrl-C will stop it. Good results should look like these and any variation indicates you have a problem with the card.
Pinging 127.0.0.1 with 32 bytes of data:

Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128

 

Newt...many thanks, got the "good results "...almost wish I had "bad results "!

 

http://broadband.motorola.com/consumers/products/signal_booster/

You may also want to ask them to test your signal strength while they are there and potentially ask for a new dedicated drop for your cable modem if it is weak.