dhcpcd-discuss

Hi Todd

On 2015-06-25 20:20, Blanchard, Todd wrote:
> It appears under linux, IPv4 client DAD does not work. I believe it
> worked in the past (perhaps previous to 6.8.2). This is an optional
> item, and is described in the RFC under section 3.1 "The client SHOULD
> perform a final check on the parameters (e.g., ARP for allocated
> network address)". Further down, it is a MUST "the client MUST send a
> DHCPDECLINE" if the client does indeed make this check. The same
> applies in section 3.2, paragraph 3.
>
> There is newer code in dhcp.c regarding IN_IFF_DUPLICATED, but this
> does not appear to apply to linux. What is the expected behavior
> regarding IPv4 DAD?

IN_IFF_DUPLICATED (and other IN_IFF_*) indicate the presence of DAD 
checks in the kernel for IPv4 addresses.
Currently only NetBSD supports this, as you point out, Linux does not.

Still, the expectation is that dhcpcd still handles the result correctly 
regardless of the kernel.
Admittedly I've not checked the behavior on Linux recently.

Roy