[Wylug-help] networking laptop woes

[Dave Fisher]

On Tue, Jul 12, 2005 at 12:45:52PM +0100, Mike Goodman wrote:
> Ping 127.0.0.1 gives no packet loss and ifconfig eth0 identifies the
> card address etc, although no IP address. Can that happen and the
> interface be missing?

Mike,

Just about everything you have said here and last night suggests that
you problem lies in the failure of your laptop to pick up an IP address
from your DHCP server.  If one is using DHCP, the content of
/etc/resolv.conf is typically written using data provided by the DHCP
server.

The obvious thing to do at this point is, to try to isolate the source
of problem, instead of thrashing about trying one thing after another.

  * Is the client failing to request an IP address from the DHCP server?
  
  * Is the client failing to make the request correctly?

  * Is the dhcp server actually recieving the request?

  * Is the server refusing to provide  an IP address in response to a
    legitimate request from the client?

The obvious place to find this information for both the client machine
and the dhcp server is in their logs.

On Debian the system log (/var/log/syslog) records incoming and outgoing
dhcp requests and their responses on both the server and the client.  

Both your RedHat laptop and your router-cum-dhcp-server will have
similar logs ... its just a question of identifying and finding them,
i.e. the stuff may be in dhcp-specific logs or generic networking logs
rather than the system log ... but I'd still look their first.

Dave