Client got wrong gateway

Rui Mao maorui2k at
Fri Feb 24 08:49:38 UTC 2017

Thank you! It works as expected now.

Best regards,
Rui Mao

-----Original Message-----
From: at
[ at] On Behalf Of
Simon Hobson
Sent: Friday, February 24, 2017 4:07 PM
To: Users of ISC DHCP <dhcp-users at>
Subject: Re: Client got wrong gateway

Rui Mao <maorui2k at> wrote:

> I installed a Ubuntu 16.04 and configured isc-dhcp-server 4.3.3 as
DHCP/BOOTp server. But the iPXE didn't got correct gateway from it.
> The DHCP server is, and the client is in another VLAN which
gateway is
> I captured Ethernet packages by tcpdump, and also used a Windows Server
2012 for comparison. It seems ISC-DHCP-Server sent a wrong gateway.
> Is this a configuration issue or a bug of ISC-DHCP-Server?

It's a configuration issue - and a known "gotcha" !

Move your class statements out of the subnet declarations - regardless of
where you define them, they are global in scope (ditto for host statements).
So a client can match a class even if you **think** you've defined it only
for a specific subnet. When this happens, the client gets options inherited
from the class in the other subnet - and a side effect is getting (in this
case) the router option from a different subnet.

dhcp-users mailing list
dhcp-users at

More information about the dhcp-users mailing list