Network in multiple shared-network instances

Simon Hobson dhcp1 at
Wed Apr 15 19:16:01 UTC 2009

Alex Moen wrote:

>So, the customers who have a MAC reservation have statements like so:
>host customer1 {
>   hardware ethernet 00:11:22:33:44:55;
>   fixed-address;
>   option routers;
>   option broadcast-address;
>   option subnet-mask;
>(DNS servers are given out globally.) Is there any reason at all 
>that I need a shared-subnet *at all* in order for customer1 to 
>receive his address???

Yes, if there is another subnet on the same wire. If the GIAddr from 
the relay says the subnet is or, then the 
client will NOT get an address in the subnet - it isn't 
valid for either of the others.

>Maybe I'm making something harder than it looks?  But what would 
>stop a customer from using that mac address at the wrong physical 
>location?  It has to tie back to a subnet statement somewhere, 
>doesn't it?

Correct, the address will ONLY be handed out to a client 
that is in the network (or shared-network).

Simon Hobson

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