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internet connection no longer working

name and version number of the Linux distro you are using? Ubuntu 10.04

I am connected to my other computer via an ethernet switch hard wired

When you are attempting to reach the internet can you see an icon

or message that states that you are connected to a network? No

it used to work just fine and I may have accidentally changed some setting

can you please help?

Andrew

Comments

  • marc
    marc Posts: 647
    Might sound stupid but... check that the wire is still connected (unplug and plug it back in )

    Regards
  • Goineasy9
    Goineasy9 Posts: 1,114
    I don't know if it was a mistake or not, but I removed your duplicate post, so, any answers will be in this one thread.
  • mfillpot
    mfillpot Posts: 2,177
    It the connection is not showing in the network manager then you may have changed the network addressing from a predefined static or dhcp/dynamic address into an incorrect static address which would cause it not to talk to the router.

    After you check the physical connection I recommend for you to check your network settings and change the ipv4 setting method to Automatic( DHCP).
  • odlevakp
    odlevakp Posts: 29
    If in the output of this command
    cat /var/lib/NetworkManager/NetworkManager.state
    

    you'll see that the networking is disabled, delete the NetworkManager.state file (and restart the service)
    sudo rm /var/lib/NetworkManager/NetworkManager.state
    sudo service network-manager restart
    
  • mfillpot
    mfillpot Posts: 2,177
    I am replying for Andrew.

    There was no wired connection and adding one did not bring it back.
    But the physical connection is active and activity lights are flashing.

    so, there may be a deeper issue, I think it would be best if you gnome guys help him through the deep diagnostics.
  • mfillpot
    mfillpot Posts: 2,177
    Please open the terminal from Applicaions->Terminal and input the commands that Pavol gave in his last post then tell us what happens.
  • Goineasy9
    Goineasy9 Posts: 1,114
    One other thing, make sure under the wired connection, you check the box that says start network automatically. If that box is not checked it may be the reason for network manager not starting. Although as said in a previous post by Pavol:
    sudo service network-manager restart
    
    should start the networking.
  • clark923
    clark923 Posts: 12
    doesn't sound stupid, I did check it & unplugged it and plugged it back in & it still doesn't work
    thanks though
  • clark923
    clark923 Posts: 12
    sorry, I'm a newbie ... how do I do this?
  • saqman2060
    saqman2060 Posts: 777
    Just some additional procedures, unplug your switch and plug it back. Then check that your router is working properly, like receiving activities, this means it is connected to your ISP. If not, restart your router by powering it off and on. Once you've done that, apply the procedures in your terminal as stated by the previous posts.
  • saqman2060
    saqman2060 Posts: 777
    To input the code, open your terminal from applications>accessories>terminal

    Then in the terminal, type as follow

    #sudo service network-manager restart

    The system will ask for your password, and once given correctly, your ethernet device will be restarted.
  • clark923
    clark923 Posts: 12
    sorry, I'm a newbie ... how do I do this?
  • clark923
    clark923 Posts: 12
    unfortunately, there was no change
  • mfillpot
    mfillpot Posts: 2,177
    clark923 wrote:
    unfortunately, there was no change

    Then you modified something even deeper in the system. Can you tell us where you made the changes that caused your network communications to fail?
  • odlevakp
    odlevakp Posts: 29
    Strange... could you open your Terminal application as mentioned before and paste here the output of these commands (some were already mentioned, but bear with me :) ):
    status network-manager
    
    network manager should be running...
    cat /var/lib/NetworkManager/NetworkManager.state
    
    everything enabled there
    ifconfig
    
    a network interface should be up
    route -n
    
    quick look on your routing table
    cat /etc/network/interfaces
    
    only loopback should be present
    nslookup linux.com
    

    dns is working... i know I've posted a lot of commands here, but the output hopefully will give the ppl in this thread a better insight on the problem...
  • clark923
    clark923 Posts: 12
    1) network-manager start/running. process 2432
    2) no such library or directory
    3) ifconfig
    lo Link encap:Local Loopback
    inet addr:127.0.0.1 Mask:255.0.0.0
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:16436 Metric:1
    RX packets:353466 errors:0 dropped:0 overruns:0 frame:0
    TX packets:353466 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:17789052 (17.7 MB) TX bytes:17789052 (17.7 MB)
    4) route -n
    Kernel IP routing table
    Destination Gateway Genmask Flags Metric Ref Use Iface

    5) cat /etc/network/interfaces
    auto lo
    iface lo inet loopback

    6) nslookup linux.com
    ^[[B^[[B;; connection timed out; no servers could be reached
  • odlevakp
    odlevakp Posts: 29
    Ok, this commands might help (I'm assuming that the cable is connected, interface is called eth0 and that there is a dhcp server somewhere on your network):

    sudo ifconfig eth0 up
    sudo dhclient
    
  • clark923
    clark923 Posts: 12
    sorry, I have no idea
  • clark923
    clark923 Posts: 12
    response from system:
    Listening on LPF/eth0/00:30:1b:81:8e:9c
    Sending on LPF/eth0/00:30:1b:81:8e:9c
    Sending on Socket/fallback
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
    DHCPOFFER of 192.168.1.68 from 192.168.1.254
    DHCPREQUEST of 192.168.1.68 on eth0 to 255.255.255.255 port 67
    DHCPACK of 192.168.1.68 from 192.168.1.254
    bound to 192.168.1.68 -- renewal in 34729 seconds.

    also, not sure what this means, but the system will automatically check the "work offline" in the file menu every time I re-try getting onto the internet (mozilla firefox)
  • clark923
    clark923 Posts: 12
    just re-started the computer and I am online again

    THANKS VERY MUCH
    All of your help is very much appreciated!
    Andrew
  • clark923
    clark923 Posts: 12
    hopefully one more quick question
    I just noticed that the "work offline" file menu is re-checked every time I go into my browser
    how do I get it to stay "online" ?
  • saqman2060
    saqman2060 Posts: 777
    cat /etc/network/interfaces
    
    only loopback should be present


    shouldn't the ethernet be present too?
  • saqman2060
    saqman2060 Posts: 777
    clark923 wrote:
    hopefully one more quick question
    I just noticed that the "work offline" file menu is re-checked every time I go into my browser
    how do I get it to stay "online" ?

    Just uncheck it, that should do the trick.
  • clark923
    clark923 Posts: 12
    yes, I understand that I need to uncheck it, but how do I get it to stay unchecked?
    it used to...
  • asedt
    asedt Posts: 96
    clark923 wrote:
    I just noticed that the "work offline" file menu is re-checked every time I go into my browser
    how do I get it to stay "online" ?

    What version of Firefox are you using?

    Maybe NetworkManager don't give the right online status to Firefox. There is a workaround here:

    http://ubuntuforums.org/showthread.php?t=851542#8
  • odlevakp
    odlevakp Posts: 29
    saqman2060 wrote:
    cat /etc/network/interfaces
    
    only loopback should be present


    shouldn't the ethernet be present too?


    iirc it's only present on a server installation, where the interface has an entry like
    auto eth0
    iface eth0 inet dhcp
    

    for dhcp, on a desktop system this should be handled by the network manager daemon
  • atreyu
    atreyu Posts: 216
    clark923 wrote:
    yes, I understand that I need to uncheck it, but how do I get it to stay unchecked?
    it used to...

    I had the this same problem w/Firefox (but in Fedora, not Ubuntu), and I tried changing a Firefox config parameter that supposedly fixed it - but it didn't. what eventaully worked for me (as Aron hinted at) was to upgrade to the latest version of Firefox. Note that my distro's repo did not have the latest version of Firefox - I had to manually grab it from http://www.mozilla.com/en-US/firefox

    hth,

    -bill
  • clark923
    clark923 Posts: 12
    I did download it but (and I know this sounds dumb, but I am very unfamiliar with how to do things with Linux/Ubuntu) how do I install this. It is currently saved on the desktop.
  • atreyu
    atreyu Posts: 216
    clark923 wrote:
    I did download it but (and I know this sounds dumb, but I am very unfamiliar with how to do things with Linux/Ubuntu) how do I install this. It is currently saved on the desktop.

    sorry, i just noticed that you responded to this...

    Believe me, it does not sound dumb.

    1. Open up a terminal (e.g., from the Panel along the top/bottom of the screen, select Applications > System Tools > Terminal or, if you are using Gnome, you can press Alt+F2, which brings up a Run Application window - type gnome-terminal then click Run.

    2. Change dirs to your Desktop directory (where the file you downloaded is), e.g.:
    cd ~/Desktop
    

    3. Make sure you see the file you downloaded, e.g.:
    ls firefox-*
    firefox-4.0.1.tar.bz2
    

    4. Unpack the archive to the /usr/local dir, e.g.:
    tar -C /usr/local -jxf firefox-4.0.1.tar.bz2
    

    NB: The above cmd assumes you are root (or own /usr/local) - otherwise, you'll have to use sudo, if your system is set up for that, e.g.:
    sudo tar -C /usr/local -jxf firefox-4.0.1.tar.bz2
    

    NB: if your firefox tarball ends in ".gz" instead of ".bz2", use -zxf instead of -jxf

    5. See if you can run it, with this simple test:
    /usr/local/firefox/firefox -version
    

    If it works, you should get back Mozilla Firefox 4.0.1 Copyright...blah blah blah
    If instead you see libstdc++/GLIBCXX errors, then your system is missing required libraries - report back to us.

    If it works, then there are various ways to make it your default, but first see if it works for you...

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