Slow network

[smolloy]

Hi Guys,
Before I describe my problem, you should understand my network layout.

  INTERNET                
     |                  
     |                 
  DSL Box
     |
     |
SuSE Desktop (192.168.10.1) (Running Apache, SSH, & a Tor server)
(Dual LAN)
     |
     |
Router (Wired/Wireless)
     |
     |
  Laptop (192.168.0.2)

So basically, browsing the web with the laptop is using the same DSL line as the SuSE desktop. The problem is that internet access on the laptop intermittently slows to a crawl, and sometimes becomes so frustrating to use that I am likely to throw it out the window! I should note that this problem has only arisen in the last 24 hours, but I am not aware of any changes I have made that could have caused this.

It's not related to the laptop network hardware since it occurs both with the wired and wireless connection. It's not the DSL line since the SuSE desktop is as fast as usual. It's not the laptop software as it doesn't matter if Ubuntu or XP is running on it.

Using the SuSE box I had a look at the network traffic between the desktop and the laptop with iftop. When someone clicks on a link on the laptop, I can see traffic start between the laptop and whatever website, but then it repeatedly stops and starts, with only a small amount of data passing each time.

To be honest I'm completely out of ideas on this one. I don't even know what I should do to to investigate this, never mind solve it! It would be great if any of you guys could give me any pointers/hints/tips.

Cheers.

[Skiboy]

You may want to check the configuration of the ethernet cards on both boxes.
The command is :

ethtool <NIC>


or


ethtool eth0


The things you want to look at are:
advertised Auto-negotiation NO
Duplex FULL
Speed 100Mb/s

If they are not set to this then set them:

ethtool -s eth0 autoneg no duplex full speed 100


Now you nic# may be different.

[smolloy]

Thanks Skiboy. I really appreciate your help.

On the laptop I get the (unhelpful) response,

Settings for eth2:
No data available

For the desktop I get a full response, and I see that advertised auto-negotiation is set to "yes" (everything else is as you advised). Before I change auto-negotiation to "no", perhaps you could explain what it means?

[smolloy]

So I tried "ethtool -s eth1 autoneg off"and now the network doesn't work at all. Unfortunately trying to get things working again by switching autonegotiation back on doesn't work. Also, the speed is now 10Mb/s, and it only allows half duplex. And, as I said, autonegotiation is stuck on "yes".

Anyone any ideas. Even a slow network is better than no network.

EDIT: I can reach the router from the laptop, but not from the desktop. And, obviously, there is no communication between the two computers. Why did switching off autonegotiation break the networking, and why isn't it a simple matter of switching it back on again?

[smolloy]

Anyone any ideas? This is killing me. Or should I say my wife will kill me if she can't get online with her windows laptop to video-skype back home to her sister.