Hi,
I had the network problem a couple day ago when I installed xubuntu (7.04) for the first time. I am hoping that I can get some help to get this resolved.

Here's how I repeated the installation procedure today;
1. install ubuntu-7.04-server (32 bit)
auto configured with DHCP.
accessible to internal network and internet with no problem.

Run the following commands in sequence,
"sudo ifconfig eth0 down"
"sudo ifconfig eth0 up"
Check internet accessibility, still alive.

"sudo /etc/init.d/networking stop"
"sudo /etc/init.d/networking start"
Check internet accessibility, still alive.

2. install xubuntu-7.04 on top of the server (32 bit)
make sure the CD drive is accessible
sudo apt-cdrom add (use alternative CD)
sudo aptitude update
sudo aptitude install xutuntu-desktop

selected NO CONFIGURATION when asked.
The install procedure downloaded 150MB data from internet.

After xubuntu-desktop was installed, I double checked that I still had access to internet. I was able to ping www.yahoo.com; www.google.com.

I checked the "ifconfig -a" output. I may need to compare it with the output when I rebooted into xubuntu.

3. reboot into xubuntu
Checked the "ifconfig -a" output with that from the server. I did not see difference. The IP address was the same as when booted to server version. The NIC was up.
But I cannot ping internal computers and internet servers.

So I run "sudo /etc/init.d/networking stop"; the following was the output:

* Deconfiguring network interfaces ...
Postconf: fatal: open /etc/postfix/main.cf: No such file or directory
There is already a pid file /var/run/dhclient.eth0.pid with pid 4377

Killed old client process, removed PID file
...
Listening on LPF/eth0/...
Sending on LPF/eth0/...
Sending on Socket/fallback
DHCPRELEASE on eth0 to <IP> port 67

From this output, the DHCP address is the same as when booted into server.

Then I run "sudo /etc/init.d/networking start".
Now it does receive DHCP offers.

I have no idea where the problem is. Did I miss anything after installed the desktop?

Harry

This same network problem exists for both ubuntu 7.04 and ubuntu 7.10 desktop. When I use the xubuntu alternative CD's rescue broken system option; I am able to detect and autoconfig the network; in a shell of the rescue env, I am able to ping internet servers.

But if I boot into the installed desktop env, I lost the network connection.

The problem is the booted desktop environment does not recognize or use the the PCI network card. It always goes to the on-motherboard card, which is disabled in BIOS. If I enable that on-motherboard card from the BIOS, I am able to connect to the world from that interface.

Now my question is,
why cannot I use the second network card, or how can I make use of the second network card?

Harry

Is it being recognised? ifconfig -a will tell you if it exists and whether it is UP or not.
What's in your /etc/network/interfaces file?

I'm not sure what you mean when you say you "install xubuntu-7.04 on top of the server (32 bit)" Do you mean you have both xubuntu-7.04 and ubuntu-7.04-server installed to the same partition?