[Dnsmasq-discuss] Reserved IP Addresses for Specific DHCP Clients without a Connection to the Subnet

[Rich Otero]

>
> is it possible that offering leases reserved by MAC don't work across
> network segments?


My client and server *are* in the same segment (VLAN 199). I made a basic
diagram showing the physical connections and the relevant layer 2 and layer
3 details:
https://docs.google.com/drawings/d/1jo6834EdFt3SWwzRkrY-eWhwmFIDDYTiKFM8fpgMwSY/edit?usp=sharing

i also don't recall seeing anything about DHCP-passthrough, DHCP-proxy, or
> similar in your original post... could it be that one of these is needed to
> facilitate this change so the address assignment can be made based on the
> MAC?


I don't think these options are relevant to me because there are no other
DHCP servers in this network segment. IP address assignment based on client
MAC address was working as expected before I removed the IP address
172.18.15.1/24 (the gateway address of this /24 subnet) from the dnsmasq
server and added it to a switch in this VLAN.

Thanks for giving it some thought.

-Rich

On Thu, Oct 27, 2022 at 5:59 AM <wkitty42 at gmail.com> wrote:

> On 10/26/22 8:34 PM, Rich Otero via Dnsmasq-discuss wrote:
> > In this new config, rack7-pdu1 does receive DHCP responses from dnsmasq
> and it
> > gets a lease. It's just the /wrong/ lease, one from the DHCP pool, not
> the
> > reserved IP address that we expect it to get.
>
> is it possible that offering leases reserved by MAC don't work across
> network
> segments? AFAIK, MAC addresses only travel within the current segment...
> once
> the traffic crosses a segment boundary, the MAC in the packet is replaced
> with
> the MAC of the boundary device... or am i remembering some ancient thing
> that no
> longer applies?
>
> i also don't recall seeing anything about DHCP-passthrough, DHCP-proxy, or
> similar in your original post... could it be that one of these is needed
> to
> facilitate this change so the address assignment can be made based on the
> MAC?
>
> just a couple of pre-c0ffee spitballs 5 minutes after wakeup...
>
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