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My computer is connected to the school's network via an Ethernet cable, but ubuntu won't recognize the network. It will scan the network for about 30 seconds and then a small error window pops up saying "Network disconnected, You are now offline".

I have been trying to fix the issue for almost 3 days now; I even re-installed Ubuntu from my bootable USB. This was a scratch install of Ubuntu 12.04 LTS via a bootable usb (which was created on my Macbook pro after I converted the .iso to a .img file) on a new computer that I just recently built. I already contacted my school's IT department, and my MAC address is registered with them. However, I am the only student running linux on the entire campus and they are unable to give me further support. I have researched the forums extensively and have tried various solutions, but none seem to work. I was advised by the IT department to leave my internet connection for IPv4 on automatic DHCP, rather than setting it to manual and copying the information from my laptop. Additionally I tried using a friends USB wireless adapter (a Netgear Wireless N-300), but Ubuntu didn't recognize the device as a wireless adapter. As a result, wireless does not appear to be a viable backup solution.

When my IPv4 is set to automatic (as recommended by my IT department) my terminal ifconfig is

Eth0 Link encamp:Ethernet  HWaddr 74:d4:45:0d:bc:b5
     inet6 addr: fe80:76d4:35ff:fe0d:bcb5/64 Scope:Link
     UP BROADCAST RUNNING MULTICAST MTU:1500 METRIC:1
     RX packets:389 errors:0 dropped:0 overruns:0 frame:0
     TX packets:0 errors:0 dropped:47 overruns:0 carrier:0
     collisions:0 txqueuelen:1000
     RX bytes:39214 (39.2 KB)  TX bytes:0 (0.0 B)
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: 65536 Metric:1
     RX packets:16 errors:0 dropped:0 overruns:0 frame:0
     TX packets 16 errors:0 dropped:0 overruns:0 carrier:0
     collisions:0 txqueuelen:0
     RX bytes:1312 (1.3 KB)  TX bytes: 1312 (1.3 KB)

When my IPv4 is set to manual and is copied from my MacBook Pro's internet configuration, my ifconfig is:

will@Anarch:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 74:d4:35:0d:bc:b5  
      inet addr:138.234.212.246  Bcast:138.234.223.255  Mask:255.255.240.0
      inet6 addr: fe80::76d4:35ff:fe0d:bcb5/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:22060 errors:0 dropped:0 overruns:0 frame:0
      TX packets:7 errors:0 dropped:3371 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:2659497 (2.6 MB)  TX bytes:461 (461.0 B)

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:65536  Metric:1
      RX packets:4597 errors:0 dropped:0 overruns:0 frame:0
      TX packets:4597 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:404944 (404.9 KB)  TX bytes:404944 (404.9 KB)

As seen in the comments below this question, here are the results for the ipshow command when IPv4 is set to automatic:

ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 74:d4:35:0d:bc:b5 brd ff:ff:ff:ff:ff:ff

Here is my nm-tool for the automatic IPv4 setup:

will@Anarch:~$ nm-tool

NetworkManager Tool

State: connecting

- Device: eth0  [Wired connection 2] -------------------------------------------
  Type:              Wired
  Driver:            r8169
  State:             connecting (getting IP configuration)
  Default:           no
  HW Address:        74:D4:35:0D:BC:B5

  Capabilities:
    Carrier Detect:  yes
    Speed:           100 Mb/s

  Wired Properties
    Carrier:         on

Here is my nm-tool for the manual IPv4 configuration:

will@Anarch:~$ nm-tool

NetworkManager Tool

State: connected (global)

- Device: eth0  [Wired connection 1] -------------------------------------------
  Type:              Wired
  Driver:            r8169
  State:             connected
  Default:           yes
  HW Address:        74:D4:35:0D:BC:B5

  Capabilities:
    Carrier Detect:  yes
    Speed:           100 Mb/s

  Wired Properties
    Carrier:         on

  IPv4 Settings:
    Address:         138.234.212.246
    Prefix:          20 (255.255.240.0)
    Gateway:         138.234.208.1

    DNS:             138.234.4.54
    DNS:             138.234.196.47
    DNS:             138.234.4.158

This is the Ping to google's server (Ip: 8.8.8.8) using Manual network settings:

will@Anarch:~$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
From 138.234.212.246 icmp_seq=1 Destination Host Unreachable
From 138.234.212.246 icmp_seq=2 Destination Host Unreachable
From 138.234.212.246 icmp_seq=3 Destination Host Unreachable
From 138.234.212.246 icmp_seq=4 Destination Host Unreachable
From 138.234.212.246 icmp_seq=5 Destination Host Unreachable

Here is a short list of failed solutions that I have already tried from other forum posts:

  • manually setting up my IPv4 based off of the information from my laptop's (A MacBook Pro) network connections
  • registering my MAC address with the campus
  • Resetting the ethernet by turning the card off and on in the Bios setup
  • Deleting and creating the network connection in the Network Connection’s window
  • Using echo on | sudo tee /sys/class/net/eth0/device/power/control
  • And other's that I can't call to mind at the moment

I'm done with classes for the day, so if anyone needs any more information please let me know. I will continue to troubleshoot for the rest of the day, so any help is greatly appreciated.

P.S. Would it be advisable to try to install a different distro of Linux and see if it can connect to the network?

Thank you, William

share|improve this question
    
Why do you copy the ifconfig stuff by hand instead of using Ctrl+Shift+C? –  the_Seppi Jan 23 at 17:16
    
Please add the output of 'ip link show' –  gnp Jan 23 at 17:17
    
Also, a list of some of the things you've tried over the last 3 days would be appreciated. –  gnp Jan 23 at 17:18
    
Are you able to connect to Internet when you boot from the Live-usb? Also, are you able to connect to Internet somewhere else? It may be a local issue. –  morphheus Jan 23 at 17:34
1  
Usually "Network disconnected, You are now offline" means your network detected but not connected. Does your school network require user name and password ? –  Prinz Jan 23 at 18:16

2 Answers 2

Could you please restart your network manager using terminal.

To open terminal press CTRL+ALT+T & then enter below command;

sudo service network-manager restart

you'll be prompted for root password, enter the password (you won't see what you're typing, don't worry its just normal) & you'll see something like below;

network-manager stop/waiting
network-manager start/running, process 3682

Once done please wait for few seconds until the network manager loads. Once done, you'll see the network notification panel which is trying to connect to any available network source. While it does it part, try to ping you localhost to see whether your NIC is functioning. To do so, try below on the same terminal;

PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_req=1 ttl=64 time=0.046 ms
64 bytes from localhost (127.0.0.1): icmp_req=2 ttl=64 time=0.044 ms
64 bytes from localhost (127.0.0.1): icmp_req=3 ttl=64 time=0.063 ms

If you see something like above which means your NIC is functioning.. if not please edit your question and post the output of what you've received.

share|improve this answer
    
My NIC is functioning, however I am still unable to connect to a network. The Network manager is still searching for the connection, as it does every time I try to connect to the wired connection 1. –  Anarch Jan 23 at 18:19
    
well if it functions which means you should be able to connect as the MAC address will remain the same even you use windows or linux. have you tried assigning IP's manually despite the DHCP just to check whether you're able to connect? –  AzkerM Jan 23 at 18:21
    
I just entered everything in manually, and I was able to establish a network connection. However, I still am unable to connect to the internet in my browser. Also, even though I just did it, the school's IT department advised me not to enter the information manually. –  Anarch Jan 23 at 18:27
    
Are they using any proxy servers?? once you connected manually have you tried pinging any websites to check whether its accessible? (If they're using proxy servers, probably that's another reason for browsing issue even though you connected to network). Have you by any-chance questioned them as to why not use manual settings (just to acknowledge yourself)? –  AzkerM Jan 23 at 18:30
    
I don't believe they are using proxy servers, and I just tried to ping google (ip address: 8.8.8.8). Here are the results of ping 8.8.8.8: will@Anarch:~$ ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. From 138.234.212.246 icmp_seq=1 Destination Host Unreachable From 138.234.212.246 icmp_seq=2 Destination Host Unreachable From 138.234.212.246 icmp_seq=3 Destination Host Unreachable From 138.234.212.246 icmp_seq=4 Destination Host Unreachable I am going to call the IT department right now to question it. I will edit this comment when I finish the call –  Anarch Jan 23 at 18:34
up vote 0 down vote accepted

Ok so I fixed it. It turns out that 12.04 LTS won't connect to the internet, I don't know why but it just won't. Anyway, I installed a 32-bit old version of Ubuntu, and its working swimmingly. My advice to anyone with a similar issue is to swallow your pride, and install an older version of the OS. It will save you A TON of frustration.

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