dhcp and Dynamic DNS -- Multi-Boot OS clients

[George Magklaras]

Look in the /var/db/dhcpd/dhcpd.leases (or wherever your dhcp leases are 
placed in your setup) and try to locate the windows and linux 
incarnation lease statements of the box in question. I would probably 
say (I can only guess) that there is a difference between the lease for 
the windows and the linux instance, in that Windows incarnations tend to 
define additional bits in their lease statements such as a 'uid' 
statement that obfuscates your MAC address with a 1 and sends it over, 
in addition to the Ethernet broadcast that makes your DHCP server aware 
of who is asking for an IP. A linux client will not use that uid bit, so 
it does not send explicitly some coded info. That's OK for DHCP, but not 
OK for your RRset DDNS ops.

If you don't make the two OSes to send #exactly# the same amount of info 
(your RRset record in DNS should use both the uid and the hardware MAC 
address to identify the system in question) the RRset record will be 
void and you will get problems similar to the ones you describe.

The key is to make the Windowz and the Penguin behave exactly the same, 
so in that case, if you have a uid statement in the Windows lease, go to 
the Linux #client# OS /etc/dhclient.conf file and issue a statement like:

send dhcp-client-identifier YOUR-MAC-ADDRESS-HERE

in order to emulate the Windows uid bit.

If it is not that, I don't know.

GM

-- 
--
George Magklaras

Senior Computer Systems Engineer/UNIX Systems Administrator
EMBnet Technical Management Board
The Biotechnology Centre of Oslo,
University of Oslo
http://www.biotek.uio.no/

EMBnet Norway:	http://www.biotek.uio.no/EMBNET/








Scott Ruckh wrote:
> I have some machines that multi-boot between Windows and Linux.  When 
> these boxes only booted a single OS the DHCP/DNS servers on the Linux 
> behaved as expected.
> 
> All the configurations and keys have been set up to allow only the DHCP 
> server to send dynamic updates to the DNS server.  This has worked fine 
> for a long time when servers were only booting a single OS.
> 
> The problem now is when the server boots between the different Operating 
> Systems, there are RR conflicts and the DNS records are not dynamically 
> updated.
> 
> In the messages log is something similar to this:
> 
> Mar  5 22:34:21 dhcpserver dhcpd: if multibootclient.example.com. IN TXT 
> "00cd2ae121c33f5e99032f48eefaefdc7e" rrset exists and 
> multibootclient.example.com. IN A 1.2.3.4  rrset exists delete 
> multibootclient.example.com. IN A 1.2.3.4: no such RRset.
> 
> I also have seen errors that state:  Can't update forward map.
> 
> I read somewhere that there exists a FAQ that addresses this issue, but 
> I have yet to find the answer.
> 
> Can someone help.
> 
> Thanks.
>