Troubleshooting Cable Modem

[lxskllr]

I've been having major connection issues since yesterday, and I've narrowed it down to my cable modem, or somewhere after that in the connection. I've had some intermittent problems in recent months, but it was so infrequent I attributed it to normal internet slowdowns. Now I'm dropping packets like crazy, and it's never a certainty whether I'll be able to connect at all. Sometimes it'll work very fast for a minute or 2, and then I'll have multiple connection resets and won't really be able to connect. Right now it's working, but very glitchy. Here's what I've done so far with no further insight...

Connected computer directly to modem (router isn't the problem)
Tried a different computer over wireless (NIC isn't the problem)

Here's a graph from PingPlotter freeware(it took several attempts to get this uploaded)...

Relevant hardware...
Rig in sig
Vista64 Business
Linksys WRT54GL router with Tomato firmware
D-Link DCM-202 modem

Any ideas on how to narrow this down further?

 

[theevilsharpie]

Use the pathping command to ping www.anandtech.com. It will collect packet loss and latency statistics on each hop, and will give you a good idea of where your performance problem is located at.

 

[lxskllr]

Use the pathping command to ping www.anandtech.com. It will collect packet loss and latency statistics on each hop, and will give you a good idea of where your performance problem is located at.

Ok, I'm not sure what this is telling me. I ran it a few times with the same results. It never makes it to anandtech, but it also tells me I haven't lost packets? It dies at hop 2 where pingplotter shows problems also.

Microsoft Windows [Version 6.0.6002]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\Dad>pathping www.anandtech.com

Tracing route to www.anandtech.com [208.65.201.105]
over a maximum of 30 hops:
0 Dad-PC [192.168.1.118]
1 unknown [192.168.1.1]
2 * * *
Computing statistics for 25 seconds...
Source to Here This Node/Link
Hop RTT Lost/Sent = Pct Lost/Sent = Pct Address
0 Dad-PC [192.168.1.118]
0/ 100 = 0% |
1 0ms 0/ 100 = 0% 0/ 100 = 0% unknown [192.168.1.1]

Trace complete.

 

[lxskllr]

Just an update...

It turned out to be Comcast's doing. I usually let problems go for a day or so because they're generally fixed within 24 hours. I gave Comcast a call today, and the computer said there were known issues with the network. Everything seems to be working great now.

I'm still interested in my question though, if anyone has an answer. Is there a way to test a modem when you suspect problems, or is it just replace and hope for the best?

 

[vailr]

Does Comcast have an online connection test?
Something like AT&T's "Self Support Tool"?
Or (without the router connected): access the modem's GUI interface via web browser. See if any troubleshooting info is available there.

 

[lxskllr]

I'll have to check out the modem. I've never logged into it directly.