[Dnsmasq-discuss] ethers should have precedence over client dhcp request

richardvoigt at gmail.com richardvoigt at gmail.com
Mon Jul 6 15:16:49 BST 2009

On Mon, Jul 6, 2009 at 2:46 AM, Michael Rack<dnsmasq.list at michaelrack.de> wrote:
> Am 05.07.2009 21:45, schrieb Simon Kelley:
> Felix Schwarz wrote:
> I have the situation that I changed the ip address in /etc/ethers. However
> when the client sends a DHCPREQUEST with its old address (because the lease
> is
> still valid) dnsmasq sends a DHCPACK and renews the lease. Therefore the
> client could use the ip indefinitely. Is that correct or did I
> misinterpreted
> my logs?
> What I would like to see is that /etc/ethers has precedence over the lease
> file. If a new DHCPDISCOVER / DHCPREQUEST comes in, dnsmasq should check the
> ethers and offer only the ip address which is written there.
> That's the designed behavior: dnsmasq should send a DHCPNAK when a
> client has a defined IP address and the client renews a lease for a
> different address. The DHCPNAK will force the client to go through the
> whole DISCOVER/REQUEST cycle.
> I suspect that your problems with duplicate IP addresses in /etc/ethers
> may have confused this, but if you have a clear case where it's not
> working, please let me have details and I'll check it out as a possble bug.
> Cheers,
> Simon.
> Hi Simon,
> i have the same probleme here. I just plugged in the network-cable to my
> VoIP-Phone (snom 360). Snom discovered for an ip-address and dnsmasq gave it
> a free address in the dhcp-pool. After that, i added the mac-address to the
> dhcp-host-addresses and set the ip-address to a different one. Snom 360
> allways got DHCPACK for requesting the old ip-address. I had to delete the
> dhcp-lease-file-entry and restart dnsmasq.

I don't think you had to delete the lease entry, you definitely needed
to restart dnsmasq because the configuration is cached at startup.
There's a signal for re-reading some files but not the main

> Michael.
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