Network in multiple shared-network instances

[Simon Hobson]

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 10.0.3.2;
>   option routers 10.0.3.1;
>   option broadcast-address 10.0.3.255;
>   option subnet-mask 255.255.255.0;
>}
>
>(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 10.0.3.2 address???

Yes, if there is another subnet on the same wire. If the GIAddr from 
the relay says the subnet is 10.0.1.0/24 or 10.0.2.0/24, then the 
client will NOT get an address in the 10.0.3.0/24 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 10.0.3.0/24 address will ONLY be handed out to a client 
that is in the 10.0.3.0/24 network (or shared-network).


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Simon Hobson

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