Thanks, working like a charm.
________________________________
From: owner-m...@openbsd.org <owner-m...@openbsd.org> on behalf of Stuart
Henderson <s...@spacehopper.org>
Sent: Thursday, June 10, 2021 12:15 PM
To: misc@openbsd.org <misc@openbsd.org>
Subject: Re: bind dhcpd to IP address
On 2021-06-10, Ralf Horstmann <r...@lists.ackstorm.de> wrote:
> Hi Valdrin,
>
> that setup works fine. You would use "ip helper-address" on the Ciscos to
> forward the DHCP requests to your OpenBSD box. The forwarded requests use the
> specified helper address as unicast destination. No need to have the VLANs
> present on your OpenBSD box.
>
> I'm running dhcpd without -u for that. dhcpd will pickup all packets with
> destination port 67 on the specified interface via bpf. No need to bind to a
> specific IP.
dhcpd will need to be listening on the interface containing the helper-address
though; if you don't want it to actually serve clients on that network, the
subnet declaration can be empty e.g. subnet 192.0.2.0 netmask 255.255.255.0 { }
> I understand your last question as: Can dhcpd provide leases for subnets when
> the dhcpd box has no IP addresses within the range? The answer is yes. You
> will
> need subnet declarations for all pools in dhcpd.conf though.
The relay includes its own address on the client-facing interface in the
relayed DHCP request; dhcpd uses that to determine which subnet to use.
