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phillywill 01-12-2010 07:28 PM

Lose Wireless Connection when Wired connection is disconnected
 
I am using a Linksys Wireless-G USB Network adapter in Ubuntu 9.10. I can connect with my wireless network when I am connected to the wired network. When I disconnect the ethernet cable, I lose the wireless connection also. Where is the best place to read about this problem? Thanks.

nimnull22 01-12-2010 07:41 PM

Hi.
Can you explain, what gives you a reason to think that when you disconnect ethernet cable you also lose wireless connection.

nimnull22 01-12-2010 07:48 PM

And actually, why do you think that when you are connected with ethernet you are also connected with wireless?

phillywill 01-13-2010 10:30 AM

When the ethernet cable is connected it shows "wired Network" connected and "Wirless Network" connected. When I remove the ethernet cable the wired network is disconnected (as it should be). The wireless connection is still connected, but I can not go online. I plug the ethernet cable back in and I can go online.

nimnull22 01-13-2010 10:45 AM

To find out if you are really connected to wireless you need to type in root console:
Code:

iwconfig
And if in output you will see "ASSOCIATED" with your wireless AP - you are connected.

Check it, and check it as well without ethernet cable.

phillywill 01-13-2010 03:52 PM

It looks as though Iam NOT connected through the wireless.

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA
Bit Rate=54 Mb/s Tx-Power=7 dBm
RTS thr=2347 B Fragment thr=2346 B
Link Quality=60/100 Signal level=60/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

william@william-laptop:~$


After I unplug ethernet cable

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA
Bit Rate=54 Mb/s Tx-Power=7 dBm
RTS thr=2347 B Fragment thr=2346 B
Link Quality=60/100 Signal level=60/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

Plug in ethernet cable and unplug wireless

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

nimnull22 01-13-2010 04:00 PM

After I unplug ethernet cable

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA


You are connected with wireless - ESSID:"william" and Access Point: 56:9E:51:35:25:AA - it means that your computer is associated with AP "william"

pomard 01-13-2010 09:10 PM

Check first if you get an ip by typing ifconfig wlan1. If you have one, it may be a routing issue. Type netstat -nr and see if there is a default gateway trough your wireless interface wlan1.

In the other hand check why your iwconfig dont show your security setting. Type iwlist wlan1 encryption
iwlist wlan1 key

phillywill 01-14-2010 06:42 AM

Thank you very much for helping.
Heres the results with the Ethernet cable disconnected wirless still connected:

william@william-laptop:~$ iwconfig wlan1

wlan1 IEEE 802.11bg ESSID:"william"

Mode:Managed Frequency:2.412 GHz Access Point: 96:1C:A6:92:CF:54

Bit Rate=54 Mb/s Tx-Power=7 dBm

RTS thr=2347 B Fragment thr=2346 B

Link Quality=60/100 Signal level=60/100

Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0

Tx excessive retries:0 Invalid misc:0 Missed beacon:0


william@william-laptop:~$ iwlist wlan1 encryption

wlan1 2 key sizes : 40, 104bits

4 keys available :

Error reading wireless keys (SIOCGIWENCODE): Operation not permitted


william@william-laptop:~$ iwlist wlan1 key

wlan1 2 key sizes : 40, 104bits

4 keys available :

Error reading wireless keys (SIOCGIWENCODE): Operation not permitted

nimnull22 01-14-2010 12:39 PM

Can you please while computer is connected by wireless type on root console:
Code:

route -n
Post, please output.

phillywill 01-14-2010 05:39 PM

william@william-laptop:~$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.42.43.0 0.0.0.0 255.255.255.0 U 2 0 0 wlan1

nimnull22 01-15-2010 10:26 AM

Ok, thanks.
I would like to explain what is going on on your computer:
When you turn it on, network manager finds two interfaces: ethernet and wireless, and configures them.
It gives them IP addresses and brings them up, but those are not enough. One need to specifies a default route, and default interface, which it sets up to ethernet by DHCP client. Wired connection works, you can go to internet.
But when you disconnect ethernet, NM removes default router, but DHCP client doesn't start again because wireless already was configured.
So, you need to reconnect to wireless, after you unplug ethernet.
Try to turn wireless OFF and ON again, and tell if it helps.

phillywill 01-15-2010 01:38 PM

I disconnected the wired connection and lost my internet connection. I then disconnected the wireless aand reconnected (i.e turned off then turned on again), but could not regain internet connection.
I tried rebooting with just the wirless reconnected and that don't work either.

phillywill 01-15-2010 01:42 PM

I also tried rebooting the router with only the Wirless connection connected, but that doesn't work either.

phillywill 01-15-2010 01:44 PM

I tried rebooting the router with the wireless connected and the wired connection disconnected, but that did not wok either.


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