Re: [lwip-users] Being notified of an address conflict when setting address manually

[address@hidden]

Mason wrote:
> IMO, autoIP is the answer to a different question. Namely, one
> wants automatic configuration, but without a DHCP server. In my
> case, there's a pre-existing network, and all I want is to
> detect a misconfiguration (human error) to be able to warn the
> user that the address he chose is already in use.

Yep, AutoIP is something different from the usage scenario. However, 
from the technical point of view, it's very close to what you want. I 
wouldn't automatically switch off the local netif though: I think it 
should be up to the application to decide whether to set the netif down 
or not. If you just set the netif down when you receive an ARP 
announcement/response that is not from your MAC, that would result in 
both devices shutting down.

I think I remember reading about duplicate address reporting when 
reading about Ethernet/IP... As none of the lwIP developers seems to 
find the time to implement this, the fastes way for you would probably 
be to just intercept ARP responses where they are passed to DHCP and 
handle them yourself.

Simon