Having both dhcp3 server and dhcp3 relay on the same host

[Simon Hobson]

Laurent CARON wrote:

>  > You can run a relay agent and a server on the same subnet, in the
>>  same way as you can run two servers on the same subnet*. However, you
>>  MUST take steps to avoid conflicts and it is generally inadvisable
>>  unless the two servers are running as a failover pair.
>
>
>Ok,
>
>I think i'll have a "real" dhcp server and a dhcp relay on this subnet.
>
>Here is how the network is built:
>
>
>192.168.10.0/24----Router----WAN----Router----192.168.0.0/24
>
>
>Would having this kind of config on my dhcp server located on the
>192.168.0.0/24 subnet be sufficient if i install a dhcp relay on the
>192.168.10.0/24 subnet ?
>
>subnet 192.168.10.0 netmask 255.255.255.0 {
>   range 192.168.10.75 192.168.10.200;
>   option domain-name-servers 192.168.10.1, 192.168.10.2;
>   option subnet-mask 255.255.255.0;
>   option routers 192.168.10.254;
>   option netbios-name-servers 192.168.0.3;
>   option tftp-server-name "192.168.10.1";
>   option time-servers 192.168.10.1;
>   option time-offset 3600;
>   default-lease-time 84600;
>   max-lease-time 604800;
>}

No, you must define a subnet declaration for the 192.168.0.0/24 
subnet as well. Ie your config file must accurately reflect your 
network.

>How the clients on the 192.168.0.0/24 subnet will get 192.168.0.0/24
>class adresses instead of getting 192.168.10.0/24 addresses?

Once you have defined the subnet, the rest happens automagically.

The server knows where the request came from (either a local 
interface or via a relay agent) and will automatically select the 
correct subnet declaration.