Dropping reply received on <downstream interface> when using -iu/-id

Brian J. Murrell brian at interlinx.bc.ca
Tue Jan 2 14:55:52 UTC 2018

On Tue, 2017-12-12 at 09:54 -0500, Brian J. Murrell wrote:
> I want to use the -iu/-id options with dhcrelay to prevent relays
> from
> relaying (and thus duplicating) requests coming from the network that
> the DHCP server is on[1]:
> # /usr/sbin/dhcrelay -4 -d -pf /var/run/dhcrelay4.pid -id br-guest
> -iu br-lan
> When I do this, DHCP Discover requests coming from clients on the br-
> guest interface have their Relay agent IP address set to the address
> of
> the br-guest interface.  When the DHCP server sends back an DHCP
> Offer
> it sends it to the IP address of the br-guest interface on the relay
> machine.  dhcrelay then proceeds to drop that reply:
> Dropping reply received on br-guest
> Is there something I am misunderstanding about how -iu/-id are
> supposed
> to work?
> Cheers,
> b.
> [1] I'm surprised this is not implicit to be honest.  The relay knows
> which network the server is on.  Why is it relaying requests that
> come
> from that network to that network?

Any ideas about this?

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 484 bytes
Desc: This is a digitally signed message part
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20180102/9af34f53/attachment.bin>

More information about the dhcp-users mailing list