[Dnsmasq-discuss] DHCPDECLINE for static addresses

Simon Kelley simon at thekelleys.org.uk
Thu Sep 20 17:57:31 BST 2012


On 18/09/12 11:45, Graham Wood wrote:
>
> I've hit a problem that seems a bit weird to me - affecting both ubuntu
> and ESX4i clients (but not esx5i). Apologies if this has been covered
> before, but I've not found anything on google that is directly related -
> just something that allowed me to work around the problem long enough to
> decide it was my fault in the dnsmasq config and not somewhere else...
>
> The following are the snippets of the config file that I believe are
> relevant. Normally this would be behind a DHCP Relay, which is why I'm
> specifying everything - for this testing, I've got it running on the
> same subnet.
>
> --
> ####################################
> # Networks
> #dhcp-range=set:infra,172.17.172.32,static,1h
> dhcp-range=set:infra,172.17.172.33,172.17.172.62,1h
> dhcp-option=tag:infra,option:router,172.17.172.33
> dhcp-option=tag:infra,option:netmask,255.255.255.224
>
> ####################################
> # Clients
> dhcp-host=set:intel,00:25:b5:00:00:7f,lab-esx1
>
> ####################################
> # Boot options
> dhcp-option=tag:intel,67,gpxelinux.0
> dhcp-option-force=tag:intel,208,f1:00:74:7e
> dhcp-option-force=tag:intel,210,"http://repo.alabs.datacom.co.nz/"
>
> --
>
> Situation 1:
> With the file as above, the ESX4i client downloads all the config files,
> including a kickstart file, and everything works fine. Install goes
> through, everyone's happy.
>
> Situation 2:
> If I disable the "dhcp-range" line, and change back to the "static"
> version that I'm using normally - ESX4i (during the kickstart stage)
> replies with a DHCPDECLINE message to the IP that it was happily using
> above - and the kickstart fails.
>
>
> I've not got the ubuntu client at the moment (it was a VM on esx5 before
> I downgraded), but it was respoding with a DHCPDECLINE too.
>
> Sooo - the question is, what have I got wrong with the "static" that is
> causing it to trigger a DHCPDECLINE?
>
> Thanks in advance, this has been doing my head in for hours (it doesn't
> help that the ESX4i boot requires 80MB be transferred to get to the
> error message)
>

The most common reason for a DECLINE is that the client believes 
something else is using the IP address offered - it checks using ARP. 
The DHCPDECLINE message can include some english text with the reason 
for the message, and dnsmasq will log that, if it exists. Might give you 
a clue?


Cheers,

Simon.

> Graham
>
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