[Dnsmasq-discuss] dhcp-range - must ip address of server be outside that?

richardvoigt at gmail.com richardvoigt at gmail.com
Mon Dec 28 04:50:09 GMT 2009


On Sun, Dec 27, 2009 at 7:46 PM, Perette Barella <perette at barella.org> wrote:
> On 2009年12月27日, at 19:47, dnsmasq.to.peejay at spamgourmet.com wrote:
>> On to another issue now: static ips outside the allocated pool.
>>
>> You seem to be implying that it is better not to define static ips in
>> dhcpserver config files (that is, it is better to have them outside the
>> dhcp range pool). Why?
>
> The obvious failure case is that you boot up a device, dnsmasq happens to give out an address via DHCP because it's in the DHCP pool... and at some later time, someone powers on the machine with the same (but statically configured) IP address.  Now you have two machines with the same IP, and suckage will ensue.
>
> So I'd agree with Rance on this one... Keep your static IPs out of the DHCP range.  dnsmasq does what it can to prevent problems, but you're opening the door to headaches.
>
> If, on the other hand, you're talking about pseudo-static IPs where dnsmasq is configured to give out a specific address from within the pool to a particular machine (via dhcp-host)... it would be nice if dnsmasq guaranteed it and wouldn't give the address out to anyone but the specific MAC address, I'd even guess that it's clever enough to behave this way, but I'm not qualified to guarantee it.  Anyone?

It doesn't appear to be part of the contract (e.g. man page) but from
experience I can say that the behavior in every version of dnsmasq
I've used is to reserve addresses mentioned in /etc/ethers or
dhcp-host lines and not give them out to non-matching hosts.


>
> Perette
>
>
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