same ip to the same mac ?

[Petre Bandac]

On Thu, 1 Feb 2007 08:15:55 +0000 Anno Domini, the honourable Simon
Hobson wrote using one of his keyboards:
> Petre Bandac wrote:
> 
> >while parsing my dhcpd logs, I have noticed a strange thing:
> >apparently, the same ip gets somehow "reserved" for the same mac
> >address
> >
> >thus, the client always gets the same ip everytime it connects
> >(which I want to prevent)
> 
> Yes this is the design of the ISC server and is (IIRC) required by 
> the RFC. Certain other servers are non compliant in this area (along 
> with a few others).
> 
> It is why you will find lease entries in the leases file for expired 
> leases, so the server can keep track of what leases it has given out 
> in the past.
> 
> The algorithm for choosing a lease for a client is (roughly) :
> 
> Has this client had a lease in it's current subnet before ?
>    If so, then give it the last address it had
> 
> Is there an unused address ?
>    If so then allocate a previously unused address
> 
> Find a previously used but currently free address and offer that. 
> This is done on a least recently used basis, and obviously once the 
> address has been reused like this then the link with it's previous 
> usage is lost.
> 
> 
> Now, why do you want the address to keep changing ?
> 
good question

the network is in a small residential area, and I would like the ip to
be as "dynamic" as possible

guess I shall keep it the way it is now


thank you for your answers,

petre
-- 

Petre Bandac

Network Scientist

-
petre at kgb.ro