[Kea-users] Need to have DHCP Relay in order for Kea to work...?

[Ubence Quevedo]

Thanks for the response.

It's not that I don't want to use DHCP Relay, I'm just a bit baffled that
the interfaces I've configured have port 67 open on them and are on the
utagged and vlan network interfaces on the server and listening where all
of the devices are on, but as soon as I turn off DHCP Relay on the pfSense
box, I don't see any DHCP traffic in the log file I've configured, which is
splitting out the packet information into its own log file.  I would expect
to see log info that the traffic is being received and DHCP requests are
being processed on the interfaces.

So I would post a log file, but there wouldn't be anything to show since
there isn't anything there.

With my Unifi equipment, I'm running the latest version of the Unifi
controller, and I've gone through the Multicast tab, and for whatever
reason, most of those options were checked to filter multicast traffic.
I'm *think* that might have been clobbering the DHCP request traffic, which
is why the DHCP Relay was the only way things were working since any DHCP
request was then re-targeted to the IP address I specified, which is what
I'm seeing in the logs.

Like I said previously, I've got things pretty wide open in pfSense between
the vlans.  All devices can talk to each other.  I would love to eventually
block traffic between these vlans, but with a problem like this, that would
make troubleshooting things a bit harder.

So it would seem there are a few disparate things [pfSense, Unifi
Controller, Kea] at play that might be getting in the way.

Any suggestions on where to look to see why things aren't behaving like I'm
expecting?

-Ubence

On Mon, Jul 15, 2024 at 12:15 AM DDFR | Ronald Blaas <ronald.blaas at ddfr.nl>
wrote:

> Not really sure how you have your network setup.
>
> But in my belief, if you want dhcp to work without RELAY you have to make
> sure your DHCP server is directly connected to all the LANs. So your DHCP
> server will need to have multiple Nics.
>
> Is  there a particular reason you do not want to have a dhcp relay?
>
> I have a kinda similar setup and am using DHCP relay. It is operating as
> expected and without problems.
>
> It is also wise to share the output of your log file with the error you
> are receiving.
> Tis helps in pinpointing the problem.
>
> Regards
>
>
> Ronald
>
>
>
> ------------------------------
> *From:* Kea-users <kea-users-bounces at lists.isc.org> on behalf of Ubence
> Quevedo <thatrat at gmail.com>
> *Sent:* Monday, July 15, 2024 00:26
> *To:* kea-users at lists.isc.org <kea-users at lists.isc.org>
> *Subject:* [Kea-users] Need to have DHCP Relay in order for Kea to
> work...?
>
> U ontvangt niet vaak e-mail van thatrat at gmail.com. Meer informatie over
> waarom dit belangrijk is <https://aka.ms/LearnAboutSenderIdentification>
>
> Hi Everyone,
>
>
>
> I’ve been using Kea for just under a year for a home setup on a Linux
> Ubuntu server.  I switched from isc dhcp since it was end of life.  My
> setup has a lot of MAC address reservations with some general pools for
> systems that don’t have IP reservations.
>
>
>
> I also have a few vlans set up with the reservations for devices on each
> of the vlans.  I’m using pfSense as my gateway with some Unifi equipment
> that is vlan aware.
>
>
>
> I’m running into an issue and I’m not sure why and would love some advice
> on how to look into this.
>
>
>
> I have the interfaces on the system setup that is running Kea, to
> advertise on the untagged network [mostly some servers], vlan 11 [user
> systems], and vlan12 [IoT devices].
>
>
>
> I don’t have the firewall in pfSense to block traffic between these
> networks yet, so they can all freely talk to each other.
>
>
>
> Even though I have my Kea configured to advertise on all of the interfaces
> [untagged, 11, 12], I can’t seem to get anything to work unless I have the
> DHCP Relay service setup on the pfSense device to redirect all DHCP traffic
> to the Kea system’s untagged IP address [192.168.10.3].
>
>
>
> I can verify through nmap that udp port 67 is running on all three
> interfaces.
>
>
>
> If I turn off the DHCP Relay service, I was expecting the interfaces to
> pick up on the DHCP requests from devices on all of these networks.
>
>
>
> This doesn’t happen and devices don’t get addresses.  I’ve even watched
> the logs I’ve split out and nothing is written for the duration that the
> relay service is turned off.  As soon as I turn it back on, I start seeing
> traffic again.
>
>
>
> I’m running Kea 2.6.0.
>
>
>
> I’d love to turn the DHCP Relay off to then try to troubleshoot another
> issue I’m having with bridging interfaces to VMs and then having the VM
> interface assigned to a vlan other than the bridged interface.  It seems to
> work for something else I’m doing, but just trying to rule some things
> out.  Probably another post if I can figure out why the DHCP Relay seems to
> need to be on.
>
>
>
> Any ideas why I need the DHCP Relay service on another device even though
> all of the interfaces on each respective vlan are configured to listen for
> dhcp requests?
>
>
> -Ubence
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