installer does not find a network - but a live system does ... wtf?

[Steven Susbauer]

On Mon, Mar 14, 2011 at 7:37 AM, Andi Meier <andimeier at gmx.net> wrote:
> *bump*
>
> in short terms: Ubuntu cannot find any working network although it is there. Here come the symptoms:
>
> (everything on the same PC:)
>
>  (case a) boot Ubuntu Live 10.04 from USB flash drive => Ubuntu is able to retrieve IP address via DHCP => OK
>
>  (case b) boot Ubuntu 10.04 from harddrive (installed system) => Ubuntu is not able to find ANY DHCP server, is
>      not even able to detect any network, also with static IP it is not able to find any network
>
>  (case c) launch Ubuntu 10.04 installer from USB flash drive => same as (case b): unable to find any network or any DHCP server
>
> How is this possible? I don't have a clue.
>
> Cheers,
> Andi

I experienced a similar issue to this when installing 10.4 in the
past. Is this a wired or wireless network? Does the interface show up
in ifconfig? Any messages in dmesg?

When I had this issue it was a wireless network card and the installer
did not install the appropriate firmware for it, but the firmware was
included in the Live version (not included in the basic installer at
all). If your issue is similar, you may be able to manually install
the firmware packages off of a usb stick. I believe configuring the
network on the Live CD was enough for it to figure out that those
packages also needed to be included, but it was hit or miss.