DHCP gives an IP when the DHCP relay is not in the subnet

Eugene Grosbein eugen at grosbein.net
Thu Jan 5 18:37:56 UTC 2017

06.01.2017 0:36, Mik J wrote:
> Hello,
> Is it possible that the dhcp offers an IP but the dhcp relay is not in the subnet ?
> I have a vlan and 3 dhcp relay. Each dhcp relay will use a loopback to relay the dhcp request or or The client machines will receive an IP in
> Is it possible ?
> NB: if there's a DHCP relay in, I don't want to offer an IP in
> Do you have a link or keywords that would help to find the typical configuration for that
> Thank you

I have same configuration and this works for me:

shared-network HotSpot {

   # DHCP relay addresses
   subnet netmask { deny unknown-clients; }
   subnet netmask {}

   # DHCP clients
    subnet netmask {
      option routers;
      option broadcast-address;

More information about the dhcp-users mailing list