[j-nsp] [EXT] Wishing for clarification on how dhcp-relay works with multiple server addresses

[Matti Saarinen]

Chuck Anderson <cra at WPI.EDU> wrote:

> On Thu, Jun 11, 2020 at 08:40:23AM +0300, Matti Saarinen wrote:
>> We have a setup where one set of DHCP servers deliver IP configuration
>> to clients and another set of DHCP servers deliver the PXE options. This
>
> Don't do that. Clients do not aggregate DHCP options from different
> responses--they pick ONE DHCP server to bind to and use the info from
> that one only. That's how the DHCP spec is written.

Actually, this setup has been working for years. I suppose the PXE code
is more flexible in that matter. In any case, it worries me that we have
been relying on a feature that may change without any notice when NIC
firmwares are updated.

Back to my question:

Based on the forum responses[1] I'd say we have to live with the
situation where we need to run dhcp-relay without forward-only on
interfaces connecting networks needing PXE. The annoying issue is that
every interface without forward-only eats one scale-subsrciber licence.


Cheers,

Matti

[1] https://forums.juniper.net/t5/forums/v3_1/forumtopicpage/board-id/IProuting/message-id/21843