[Dnsmasq-discuss] 3 secs dhcp delay

[Roy Marples]

On 17/01/2019 22:58, Simon Kelley wrote:
> The delay is while dnsmasq tests the address it's about to allocate in
> case some host is already using it. It sends a ICMP echo request
> (essentially a ping) and if it gets a reply, the test fails. After a 3
> second timeout the test succeeds and the address is allocated. If you're
> happy that there are no machines using IP addresses without leasing
> them, or that the similar test that DHCP clients do will find this, then
> you can disable the check in dnsmasq using the --no-oing config flag.

NetBSD and Solaris do IPv4 DaD checks using ARP in the kernel, so the 
DHCP client doesn't strictly have to do anything other than listen to 
the kernel notifying the DaD result.

Roy