[Kea-users] Help! Kea 1.1 sends unicast, breaks iPXE

[Ledochowski, Roy]

Thank you also for the reply Francis.  Is this something I should ask about on the  iPXE dev list?

-----Original Message-----
From: Francis Dupont [mailto:fdupont at isc.org] 
Sent: Friday, January 06, 2017 1:17 AM
To: Attila Szalay <mochrul at gmail.com>
Cc: Ledochowski, Roy <roy.ledochowski at hpe.com>; Klaus Steden <klausfiend at gmail.com>; kea-users at lists.isc.org
Subject: Re: [Kea-users] Help! Kea 1.1 sends unicast, breaks iPXE

Attila Szalay writes:
> I'm not around my machine, but if I remember correctly there is a flag 
> in the dhcp request that mandate using the broadcast in the answer. 
> Without that flag the unicast is favored. So, the question is if that 
> flag is set by the iPXE client? If yes, then it is definitely a bug in 
> kea, otherwise I'm not sure.

=> there is such a flag (it is the only defined flag cf RFC 2131 figure 2 (format of flags) and section 4.1). Note that if it is set to 1 the server or relay is required to use IP and link-layer broadcast, but not the opposite (i.e., 0 does not imply unicast).

The ISC DHCP client built in standard way always sets this to 0 (*), ISC DHCP relay and server follow it for bootp and dhcp, Kea server too (cf Dhcpv4Srv::adjustRemoteAddr code).

(*) this suggests this flag is rarely set by clients in queries.

Regards

Francis Dupont <fdupont at isc.org>