[Dnsmasq-discuss] DHCP Address - Lease in numerical order

[Simon Kelley]

Eric Arnoldy wrote:
> Hey All,
> 
> I've looked everywhere and can't seem to find mention of it, but does
> dnsmasq support DHCP addresses being handed out in numerical order?

No.
> 
> I want the first box connected to get .100, then 101 for the next one
> and so forth.  I see there is some logic in there to check and see if
> its already been taken, but from what I see here, the addresses that I
> get appear to be random.

It's not random: the address is derived from the start and end addresses 
of the address pool and a hash of the MAC address. This means that a 
given host will (nearly) always be offered the same address, without 
dnsmasq having to keep track of the addresses allocated in the past to 
hosts which don't have a lease right now.

The alternatives are  it to keep a much bigger database which has 
historical information about all leases offered to all hosts for all 
time (ISC), or not to attempt to give hosts stable addresses at all 
(udhcpd). I thought the hash-function trick was a particularly neat 
alternative.

> 
> I am specifying a start and end for the pool using the dhcp-range, but
> I guess thats just possible addresses, not where it will acutally
> start giving out addresses.
> 
> Anyhelp, or assistance in this matter would be much apprecieated.

If you really want to, you can patch the code, but I'm not convinced 
that the gains outweigh the losses.


Cheers,

Simon.


> 
> Thank you!
> Eric Arnoldy
> 
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>