Request on offered address gives "unknown lease"

Peter Rathlev peter at
Wed Oct 25 10:35:01 UTC 2017

On Tue, 2017-10-24 at 13:10 +0200, Peter Rathlev wrote:
> We're testing some new software on a client device (a switch) and can
> see that it doesn't get an IP address lease correctly.

I tried capturing a request from an older device and am seeing a clear
difference. Specifically the newer (not functioning) software fills out
the "Client-IP" (ciaddr) field with where the old does
not, i.e. leaves it at all zeros.

As I read RFC2131 any client requesting a fresh lease (not renewing)
should never fill out ciaddr. In this case it uses,
which is clearly invalid, but it's still wrong.

This means we have something to go to the vendor with.

Assuming this is the reason dhcpd doesn't answer the request, is there
a handle to make it accept packets with wrong ciaddr, just to make sure
this is the actual and only error?

Peter Rathlev

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