Internet Connection Cuts Out

[ddeeff]

My (Windows XP) computer is having trouble with its internet connection.

I'll give 2 examples of the same problem.

1. I'm downloading a webpage. Sometimes, esp. on longer pages, not everything downloads. At some point, the connection has failed mid-download. However, the browser carousel which represents the loading of the page is still spinning.
   
2. I'm downloading a file to my hard drive. It cuts out and the information it displays (time remaining, X of Y MB, speed) doesn't update (should say 0kb/sec, but displays speed before cut-out). It does this on IE and Fx. The only way to download a whole file is normally to keep pausing and resuming until the whole thing is downloaded. This is a pain is the ass.
   

Additional information:

I have isolated the cause as a problem with the computer since the same problem is occurring at two different residencies whilst my (Vista) laptop has no issues at both locations. Additionally, the issue occurs with both wired and wireless connection.)

f I am downloading multiple things, they do not cut out at the same time.

It is not a set MB before it cuts out. It's random. Sometimes it'll cut out quickly, other times it'll go longer!

I don't believe the problem is Malware. I've had the problem for almost a year and frequently update and run Spybot and Ad-Aware

[shanenin]

I would try both pinging in regular mode and in "safe mode with networking". they should be very steady and regular. It may help you isolate the problem. If the pings are smooth only with "safe mode with networking", you may be able to isolate what is booting in regular mode which might be causing the issue

ping google.com -t

the -t option will allow the pings to keep going untill you stop them

[TheTerrorist_75]

Spybot S&D and AdAware will not detect all malware. In fact I quit using them some time ago. You should have a good anti-virus program installed. Another good program to detect and remove malware is MBAM.

[ddeeff]

Thanks for the replies,

I have pinged google.co.uk (closer) and google.com without comparing it to the safe mode with networking

They give similar steady responses. (42ms and 122-124 respectively). I don't think the ping response is a large enough amount of data to trigger the error.

I wanted to instead test whether the problem I described occurred (using a browser) in safe mode with networking, but I couldn't get online. I'm using a wireless Belkin adapter to connect to the router, which is connected by a USB port. It uses a Belkin application to connect to the router, but this application seems not to be able to detect the adapter. (My USB keyboard and mouse work fine).

Any suggestions on getting it to work in safe mode so I can test for the problem?

Edited August 30, 2009 by ddeeff

[jcl]

They give similar steady responses. (42ms and 122-124 respectively). I don't think the ping response is a large enough amount of data to trigger the error.

Ping uses one small packet, so, yeah, if it's related to the size of transfer that probably won't trigger it.

One thing you might try: in Firefox browse to about:config and set network.http.keep-alive to false (you can use the filter field to find it quickly). That will (or should) force Firefox to use a fresh connection for each request instead of reusing connections. You might also reduce network.http.max-connections-per-server to 1. If that reduces or eliminates the partial page loads, it's likely that it is the size of the transfers that's the problem.

(But wait, you say, I would still be transferring the same amount of data. You're right. In fact, you'd be transferring more data. This is really a quick way to determine is there's something weird happening with TCP and a very stupid way to throttle Firefox. I have no idea why large transfers over single TCP connections specifically would cause problems but I have a router that seemingly exists just to prove that it can happen.)

If that is the problem... I dunno. I had a router that randomly dropped connections during large transfers because its MTU was too high for the network (never did figure out why it worked the most of the time), but I'd be surprised if your desktop and notebook were using different MTUs.

[ddeeff]

Thanks again,

I'm not sure that it's large transfers that are the problem, I think the error is statistically more likely to occur in large transfers because there's more time for it to go wrong.

network.http.keep-alive seemed to have no effect, but setting network.http.max-connections-per-server to 1 made a large page of text unable to load at all. I switched it back to 15.

Perhaps Firefox is making loads of connections and only some of those work. It then uses the working ones to download data until one by one, the connections fail and there are no more connections to serve data. This doesn't explain why all the pings were successful, unless pings use multiple connections... I don't know... it's useless for me to guess like this.

As a final experiment, I switched network.http.keep-alive back to true and network.http.max-connections-per-server to 1. It failed, so it looks like network.http.keep-alive is having no effect at all

Edited August 30, 2009 by ddeeff