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I have a Dell inspiron 1726 laptop. When I try to connect to the Internet via my wired network it drops packets. (I can access the Internet just fine from another computer, so the problem is with the laptop).

I tried uninstalling and reinstalling the NIC but that did not help.
I also disabled firewall but also no luck.

When I test with ping 192.168.xxx.xxx -t I get this output:

reply from 192.168.xxx.xx ......
reply from 192.168.xxx.xx ......
reply from 192.168.xxx.xx ......
reply from 192.168.xxx.xx ......
request time out
request time out 
request time out
reply from 192.168.xxx.xx ......
reply from 192.168.xxx.xx ......

It goes on like this.

When I browse a web page it takes ten to fifteen minutes to open that page.

And it is strange that it just works perfectly on my desktop. Any ideas?

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Is the network card configured to always use full duplex? (Rather than auto detect). –  Hennes Jul 19 '13 at 15:46
    
@Hennes: How do i do that? –  user239295 Jul 19 '13 at 18:24
    
That depends on the cards drivers, so there is not generic answer to that. But to explain what it is. 10Mbit and 100Mbit Ethernet uses 4 wires (2 pairs). In Half-duplex mode one pair is used to signal 'please wait, I am going to use the remaining pair to sent you some data' and the other pair is used for the data. In full-duplex mode one pair is used to sent data, one pair to receive data. If there is a miss match between these settings on the laptop and on the switch then you get all sorts of weird things, including dropped frames. Disclaimer: Usually the default settings are fine though –  Hennes Jul 20 '13 at 11:01
    
@Hennes: Its working like a charm, you just made it. When I changed it to 10 mbps with full duplex. from auto negotiation. Thank you. –  user239295 Jul 20 '13 at 20:17
    
i accept your solution as an answer. thank you so much, its perfect now. –  user239295 Jul 23 '13 at 21:31

2 Answers 2

up vote 0 down vote accepted

If the network card is configured to always use full duplex when the other side expect half duplex then you get symptoms as you described.

Usually a NIC comes with a few options:

  • 10/100/1000 mbit
  • Always half duplex, always full duplex, or auto detect (Which usually works).

How you set a card to such a mode depends on the drivers. For unix linke OS's if is usually done with ifconfig. On Linux you can use either ifconfig or ip link. In windows there is no fixed location to set it, it seems to depends on the driver. (It is quite often found under the NICs properties though).


Some background as to what half- and full-duplex are:

10Mbit and 100Mbit Ethernet uses 4 wires (2 pairs). In Half-duplex mode one pair is used to signal 'please wait, I am going to use the remaining pair to sent you some data' and the other pair is used for the data.

In full-duplex mode one pair is used to sent data, one pair to receive data.

If there is a miss match between these settings on the laptop and on the switch then you get all sorts of weird things, including dropped frames, working connections despite the card claiming 'No link', dropped connections, ...

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More details would be welcome, but since i can't make any comments i'll give a shot.

Do you have a fixed ip address specified on your network card on your Laptop ? If you do try set it to obtain an ip address automatically (DHCP).

To reset all your network settings execute the following commands in the command line:

ipconfig /flushdns
nbtstat -R
nbtstat -RR
netsh int reset all
netsh int ipv4 reset
netsh int ipv6 reset
netsh winsock reset

Reboot.

Source:Scott Hanselman's Blog

If after this you still don't have internet, you'll have to check your router for other settings, or try a different cable.

Provide more details and i'll try to help you.

Edit: Does your Desktop have also fixed ip address ? Have you compared the network settings between your desktop and Laptop ?

Execute ipconfig/all on your desktop and laptop and compare the output.

**Edit2: It seems your laptop needed a driver update from Dell

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I have a fixed ip address. The cable is just finely working with my desktop. –  user239295 Jul 19 '13 at 18:23
    
My desktop also have the same network configuration...no difference between my desktop and laptop network settings. They both share the same fixed ip with the same wired connection. –  user239295 Jul 20 '13 at 19:19
    
One more thing the command which you posted worked fine but just only for five minutes, internet was just working fine. But then it again started to lag, same situation. –  user239295 Jul 20 '13 at 19:22
    
Thank you for your help. –  user239295 Jul 20 '13 at 20:19
    
Hmmm, have you tried to update your drivers ? BTW i can't find your laptop model on your website, are you sure it's the correct one ? –  Calbertoferreira Jul 20 '13 at 22:45

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