[Dnsmasq-discuss] DHCP Option 12 (Hostname) problem

Raymond Lillard rlillard at sonic.net
Wed May 9 02:57:11 BST 2012

Dear DNSMASQ'ers

I am developing code for an embedded micro controller with
a network interface.

I am presently working on the DCHP client code where dnsmasq
is both name server and dhcp server.  The dnsmasq OS environment
is OpenBSD, although I doubt the OS is a factor here.

While I am by no means new to network programming, I have
never actually written code to make DHCP happen before so
I am learning new details as I go.

I am considering how to handle the case where the client
(my controller) asks for a specific hostname in its DISCOVER
and REQUEST messages and I know that specific name is not
available because it is committed to an unexpired leaseholder.

In no case is dnsmasq responding to my client's option 12
in its OFFER or ACK messages.  By that I mean, in cases of
a clear name being requested or in cases where the requested
name is in conflict with an already committed name, I see
nothing from dnsmasq on option 12.

In cases where the name does not conflict, the DNS side of
dnsmasq will resolve the requested name correctly.

The only unusual dnsmasq thing is I am restricting the IP
address range for my controllers as shown:


I admit I have not tested against any other DNS/DHCP servers
and I don't want to bring up the ISC bind/dhcp atrocity
just to get another data point.

I'm wishing some kind soul can slap me with a clue stick,
for which I will be most grateful.  I can and will happily
supply actual logs, configs and wire transcripts if needed.

I'm hoping I've overlooked something and its only me that
needs debugging and not dnsmasq.


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