Mapping a MAC to an IP...

Chuck Anderson cra at WPI.EDU
Wed Jan 21 17:01:37 UTC 2009

On Wed, Jan 21, 2009 at 10:16:34AM -0600, Peter Laws wrote:
> Simon Hobson wrote:
>> Host declarations are global in scope, and so are valid even if a  
>> client is connected to a different subnet (in which case it will get a 
>> dynamic address from that subnet rather than the fixed address). But 
>> what would happen is that the client would get a suitable IP address, 
>> but inherit options (such as routers) from the subnet where the host 
>> statement is declared - I think you can imagine the confusion that 
>> causes !
> That makes no sense ...  if a particular host connects to a different  
> subnet, I'd want it to get the information *appropriate for that subnet*, 
> not the one where it may have a static IP/reservation/whatever you want 
> to call it.   What am I missing?

Put subnet-specific options in the subnet {}, and host-specific 
options in the host {}.  Do not put host {} inside subnet {}.  
fixed-address is the exception here, because it is both 
"subnet-specific" and "host-specific".  The DHCP server is smart 
enough to use one of the fixed-addresses declared in the host if one 
of them is valid for the subnet from which the request came, otherwise 
it will assign out of a subnet pool.

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