Detecting Loss of Data Stream in LAN

On a sunny day (Wed, 05 Nov 2008 17:43:15 GMT) it happened snipped-for-privacy@hotmail.com (Terry) wrote in :

What exactly do you mean? I dunno about MS Widows soft, but I run a similar system with Linux.

There is a whole lot of tools available.

I use 'snort' to monitor traffic

Maybe you can run a Linux PC. You can make it look at specific packets, ports or IP addresses, have it log data, look at the contents of packets in ASCII, etc.

Other useful tools are: traceroute to follow the path of a connection to an IP address. ping to get delay times route about yor routing ifconfig to see your configuration netstat to see who is connected

I think you need no hardware. You likely have some router, and that router may have NAT tables, a server DNS server, DHCP for auto network configuration, you should at least check that those are correctly configured.

Get Linux.

All the tools are free.

From the message source it seems you are using AT&T like I do. If that is true or it's another DSL provider check the levels. I don't remember what they should be but many moons ago I also had unreliable web connections. Looked it up on the web, measured, scratched my head. Disconnected the phone line from the office to the house -> Internet worked great. Turned out one phone in the house had been plugged in without a DSL filter. Fixed that and if worked happily ever after. Well, until a kid in a souped up car spun out and took out a big gray box.

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Use another domain or send PM.

A good E-mail program (like Eudora Pro) will log server failures. I have mine set to retrieve mail every 15 minutes. Timeouts get logged.

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
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Terry,

Depending on your modem, you should be able to access it and get the line stats. Check your manual for more info, or ask your ISP if he can get them from his end. The stats will give your SNR which tells how good the line is. Your ISP can explain more.

Next, monitor your TCP/IP speed online with Analogx NetStat (free):

Also check for more useful stuff here:

There are many DSL speed test sites. A lot of them are crap. Here are two good ones. Both require Flash:

1. Check speed to different cities in USA:

1. Check speed to different cities around the world:

Regards,

Mike Monett

[...]

Here's some more info. Your ISP can tell when the modem dropped the connection. If the SNR is very poor, the modem will lose lock and have to resync, which can take a long time.

If the problem is SNR, you need to call your telephone repair and get them to investigate the line. If you live a long way from the switching point, you may have to find another modem that can cope better.

You can check some things yourself. Lift the phone off hook and press a number other than "0". This will stop the connection signal so you can listen for any noises.

If you hear the slightest scratching or click, you need to find out why and fix it. It may be very weak, but the slightest noise is enough to cause problems.

It could be caused by running the telephone line too close to a SCR dimmer-controlled appliance, such as a fan. Or maybe you have the cord for a laser printer next to the phone line. The heater thermostat generates huge spikes that could obliterate the DSL signal. Maybe the thermostat in your Weller soldering iron is causing problems.

You could have an intermittent connection somewhere. Here's some examples:

1. I had a scratchy telephone line that turned out to be the demarck connection in the basement. Years of accumulated crud and corrosion made a poor connection. I cleaned it with ordinary Vaseline, which lifts the crud and oxide coating and allows a true metal-to-metal contact. This reduces the contact resistance by an order of magnitude and stabilizes it. You may need to reappy it every six to nine months. If that doesn't work, buy a new one and replace it.
2. My DSL kept dropping the connection, same as yours. I live less than 1km from the main office, so the SNR is excellent. It turned out to be a bad power supply. The voltage was marginal, and if the line voltage dropped a slight amount, the modem lost lock. A new power supply helped, but I still had random disconnects.
3. It turned out the neutral connection for the outlet that powered the modem was never tightened in the main electric panel. The wire was just resting against the bussbar. Any movement due to vibration or temperature changes would break the connection. Tightening the clamp screw solved the problem.

The moral of the story is random disconnects can be difficult to find, but if you keep an open mind, eventually you can track them down and fix them.

Best Regards,

Mike Monett

Terry--

Hopefully you have a router with a hardware firewall between your ISP's box (cable or DSL modem) and your machines.

Most routers have the ability to generate logs for events such as incoming hits on the firewall. Linksys certainly does.

If you turn this feature on and send the data to a machine that can watch it (hint: a free Windows program called Wall Watcher), you'll notice that nasties are banging on your machine all the time!

I use Wall Watcher and some other software to record the logs from the router.

If the router doesn't see any assaults from the outside in 5 minutes, the internet must be down!

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Namaste--