Re: linux does not response gratuitous arp request?

Hans wrote:
I'm testing dhcp with conflict ip.
As my understanding, when dhcp server assign an IP to a windows
PC(pc1), pc1 will send out an gratuitous arp to confirm if there is
another PC using the IP. if another PC(linux,pc2) is using the IP,
then pc2 should send out an arp reply to claim it's using it, then pc1
will send out dhcp decline packet to dhcp server and request another
IP.

But, in my test, pc2 does not response the gratuitous arp request at
all, why? if PC2 is windows OS, it will response it. So, for the
linux case, IP address conflict problem will occur. Is this by
design? (if it is, how can we avoid the address conflict problem?)


If the linux machine gets an ARP request, it will respond with an ARP reply. This has to be working if the linux box is able to communicate over the subnet. If you're not seeing that behavior, perhaps some router or Ethernet switch is preventing the ARP request from reaching the linux machine, or preventing you from seeing the response.

another problem is : when a linux PC was assigned a new ip, it will
just use it anyway, without sending gratuitous arp to check if there
is a conflict, but windows PC will.


Sorry, I can't comment on this behavior.

Why does the linux and windows behave different so much?

Thanks


--
Steve
.

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