Cannot connect to wired network

[hounddog]

Hi Guys,

I have a strange problem. I have been trying to install Ubuntu 12.04 over the weekend but there seems to be a problem with the internet connection after installation.

The LiveCD works fine, I can connect to and surf the internet from the Live Session. But after installation and logging in into the desktop, the system cannot connect to the internet. It just says the network connection is disconnected and I am in offline mode. I have tried deleting the wired connection account and enabling a new connection but it didn't worked. It just doesn't seem to be able to find my NIC or IP, unlike the Live Session. It also messed up my router and I've had to reset it every time after logging in into the installation.

I repeat that the Live Session works fine. It's the install that has the problem. I have tried upgrading during the installation but I still have the same problem after logging into the desktop.

Anyway, my motherboard is an Asus P5VD2-MX SE and I use the onboard NIC which is a Realtek RTL8201CL 10/100M LAN.

I reinstalled Natty Narwhal, which is what I was using before and it works fine.

Any comments or pointers would be welcome.

[sikander3786]

We need the outputs of these commands please:

ifconfig
cat /etc/network/interfaces
cat /etc/udev/rules.d/70-persistent-net.rules

[hounddog]

We need the outputs of these commands please:

ifconfig
cat /etc/network/interfaces
cat /etc/udev/rules.d/70-persistent-net.rules

Hey, thanks for the reply.

I'm not going to be able to give you those outputs since I've already replaced 12.04 with 11.04. Maybe in the near future when an updated 12.04 comes out, then I'll try installing it and see if I have the same problem.

[Spez1]

Hi all,

I'm having trouble connecting to a wired network as well on my 12.04 LTS (works just fine with Windows 7). I can see the network but the connection just ends up retrying constantly with no connection.
ifconfig

eth0      Link encap:Ethernet  HWaddr 14:da:e9:04:bb:8c  
          inet6 addr: fe80::16da:e9ff:fe04:bb8c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6 errors:0 dropped:0 overruns:0 frame:0
          TX packets:52 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:384 (384.0 B)  TX bytes:10800 (10.8 KB)
          Interrupt:18 Memory:fb400000-fb420000 

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:605 errors:0 dropped:0 overruns:0 frame:0
          TX packets:605 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:49002 (49.0 KB)  TX bytes:49002 (49.0 KB)

usb0      Link encap:Ethernet  HWaddr 36:d8:4a:0e:cb:c7  
          inet addr:192.168.42.15  Bcast:192.168.42.255  Mask:255.255.255.0
          inet6 addr: fe80::34d8:4aff:fe0e:cbc7/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3676 errors:1 dropped:0 overruns:0 frame:1
          TX packets:3003 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3655712 (3.6 MB)  TX bytes:498963 (498.9 KB)

cat /etc/network/interfaces

auto lo
iface lo inet loopback

cat /etc/udev/rules.d/70-persistent-net.rules

# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.

# PCI device 0x8086:/sys/devices/pci0000:00/0000:00:19.0 (e1000e)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="14:da:e9:04:bb:8c", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

The funny thing is I can connect fine by tethering my phone but there obviously is something wrong with the ethernet card (drivers) but I just can't figure what...

[sikander3786]

@Spez1:

Are you sure it isn't a problem with the LAN cable or the connector? You mentioned that it works fine with Windows 7 but I still want you to check the cables as all the configuration seems pretty ok to me.

How do you connect to the network? Shared connection, router, cable network? Are you sure Windows 7 wasn't fed manually with addresses and you've got an active DHCP server running on your network? If you are connecting via an ADSL Router, chances are that DHCP server is running, still, just re-check.

If that isn't the problem, note down your IP address, Gateway, Subnet Mask and DNS from Windows 7 and feed it manually in Ubuntu. See if that works.

[Spez1]

The connection goes via a router I guess. Windows 7 got its address automatically. Now that I manually entered the IP address etc the network works ok. Don't know if this is a permanent solution.

edit: Turns out it wasn't. After some time the address expired. There is something fishy with DHCP in ubuntu...

[jcs3rdma]

Same problem. Desktop->upgrade to 12.04 and no wired connection.

http://www.liberiangeek.net/2012/03/...neiric-ocelot/

Followed steps from above to disable the network manager and added the eth0 entry. Now 12.04 works. Be nice if it worked after the upgrade without all this trouble.

[firekage]

Can you explain these commands in this:

http://www.liberiangeek.net/wp-conte..._oneiric_3.png

what does mean:

auto lo
iface lo inet loopback
iface eth0 inet static

Thank You.

[jcs3rdma]

Not real sure myself. Just sort of experiment. In my copy on the /etc/network/interfaces file, I only added the following.

auto eth0
iface eth0 inet dhcp


What does it mean? Not exactly sure but I will take a stab:
iface -- interface
eth0 -- ethernet port 0
inet -- "internet" ?? not sure
dhcp -- I changed this to dhcp because my router will assign an address.

hey, linux is something to experiment on and learn. It was not working before, I knew the changes I was making and could always go back if it did not work.
fun times.

[hounddog]

Not real sure myself. Just sort of experiment. In my copy on the /etc/network/interfaces file, I only added the following.

auto eth0
iface eth0 inet dhcp


What does it mean? Not exactly sure but I will take a stab:
iface -- interface
eth0 -- ethernet port 0
inet -- "internet" ?? not sure
dhcp -- I changed this to dhcp because my router will assign an address.

hey, linux is something to experiment on and learn. It was not working before, I knew the changes I was making and could always go back if it did not work.
fun times.

Hey thanks for that. I'll probably be installing 12.04.1 next, and if it does the same thing as 12.04 I'll use your method and disable network manager and enable the internet connection manually.