Adding DHCP to system that was installed with no network access

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Am Do, 14. Mai 2009 16:14:35 schrieb Dotan Cohen:
> I had to install Ubuntu 9.04 on a system that was not connected to a
> network at the time of install. Now, the system cannot find the home
> network (DHCP assigned from a consumer router). 
a) The system cannot find the local network?
   E.g. a ping to a local IP in your network doesn't work
   

b) Or the systems network-card doesn't get an IP from your DHCP Server
   E.G. an ifconfig eth0 shows no IP for your network-card.

> Installing in another partition on the same machine while connected to the
> network makes the machine find the network with no problems.
>
> How can I repair the unnetworked installation? Thanks.

- For a) 
Check your /etc/resolv.conf file(s) You might see a difference between the 
resolv.conf file on the computer which has network connetivity and the one 
which has not.


- For b)
Open /etc/network/interfaces in an editor and check if the dhcp option is set 
for your network-card (NIC):

Open a Terminal and type

  sudo editor /etc/network/interfaces

You will see the file opened in your systems favorite editor.

For your NIC it should have an entry like the one below:

---8<---
auto eth0
iface eth0 inet dhcp
---8<---

regards,
thomas