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.