Replies to request coming over a relay goes to relay's internal IP, not to original request's source IP

Oguz Yilmaz oguzyilmazlist at
Sun Oct 7 08:03:12 UTC 2012

I understand what you mean. According to basic networking this does
not seem meaningful for me. DHCPD does not reply to the asking relay
server: > BOOTP/DHCP, Request from
00:1e:68:06:eb:37, length: 300, hops:1,
	Gateway IP:
	Client Ethernet Address: 00:1e:68:06:eb:37 [|bootp] > BOOTP/DHCP, Reply, length: 300, hops:1
	Your IP:
	Gateway IP:
	Client Ethernet Address: 00:1e:68:06:eb:37 [|bootp]

However, if you say this is how it works, I have nothing to say but thank you.

According to your comments a client for example can
directly try to talk with So we should always have right
path to in routing table of dhcpd server.

Thank you.


On Sat, Oct 6, 2012 at 7:17 PM, Simon Hobson <dhcp1 at> wrote:
> Oguz Yilmaz wrote:
>> HOWEVER, I have deleted route on dhcpd server to reach 172.16.17.x
>> subnet.
> Then your network setup is broken. Fix your routing tables so that the
> server can send unicast packets to devices in the 172.16.17.x subnet. Don't
> forget that clients will normally renew their leases by unicast requests
> direct to the server - so there must be a route for both the request and the
> reply.
> This is very basic IP networking you are getting wrong here.
> --
> Simon Hobson
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