Re: Urgent: Query on dhclient in handling IP conflict

[sathya sai <sathyasai.eshwar@gmail.com>]

Hi All,

I COULD FIX this problem with the following solution,

I could distinguish the IP conflict in the network by using following command in dhclient-script. We need to install “arping” debian package for this.

arping -d -I eth0 -c 3 {IP address got from DHCP server}  >/dev/null; echo $?

The above command will return “1” if IP conflict doesn’t exist and returns “0” if IP conflict exists.

And when IP conflict is detected, exit from dhclient-script with positive exit status. dhclient already has a code to send DHCPDECLINE packet (with which dhcpserver will assign a new IP to the dhclient client) when dhclient-script returns  positive value.

Hope this helps !!

Thanks and regards,
Sathya

On Tue, Dec 22, 2009 at 8:36 PM, Boyd Stephen Smith Jr. <bss@iguanasuicide.net> wrote:

In <a30ddc1c0912210639h491a727ep5860eedd88118112@mail.gmail.com>, sathya sai
wrote:

>I had already thought on these possiblities. But the problem here is, we
>dont have control over neither our DHCP server (it can be either Windows or
>Linux based servers) nor the client PC which configures static IP (anybody
>in the subnet can configure the IPs on their wish). I hope, this is true
>with the real time deployment scenario.

Wait, what?  You don't control the server AND you don't control the clients
AND you want to change how the server and client interact?  I'm sorry, I think
you are asking for the logically impossible.
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