DHCP and DDNS

[Gregory Hicks]

> Date: Thu, 3 Apr 2008 14:09:59 -0700 (PDT)
> From: X O R <imperia777 at yahoo.com>
> 
> I did exactly that. reserved several addresses via fixed-address
> option in dhcpd.conf.
>
> maybe the correct way to do this is to make static dns entries for
> the static ip addresses.

What you lose, when you do this, is the ability to take the machine
from one subnet and plug it into another and "just have it work".

The other thing you lose is the ability to plug in another machine in
to the subnet and possibly get the "reserved" IP assigned to it - if
the machine for which it is reserved is not present on the network.

Static DNS IP entries are good if the machine has no possibility of
moving - ever - to another subnet.  If there is that possibility, then
DHCP can be the way to go.

We have most of our 38K machines configured to use DHCP.  Even most of
the ones that require a fixed IP.  This allows us to take a machine
from one building to another and "just plug it in" and have it come up
working.  Those machines that require the same IP address, from lease
to lease, have the IP address "reserved" by MAC.

Regards,
Gregory Hicks

> 
> ----- Original Message ----
> From: Gregory Hicks <ghicks at cadence.com>
> To: bind-users at isc.org; kcd at chrysler.com
> Sent: Wednesday, April 2, 2008 5:30:05 AM
> Subject: Re: DHCP and DDNS
> 
> 
> > Date: Tue, 01 Apr 2008 19:19:31 -0500
> > From: Kevin Darcy <kcd at chrysler.com>
> > To: bind-users at isc.org
> > Subject: Re: DHCP and DDNS
> > 
> > X O R wrote:
> > > Hello,
> > >
> > > I was trying to setup DHCP server to update connected clients into
> > > BIND9. Its working now. The problem is that I have few hosts with
> > > static ip address defined using fixed-address option in 
dhcpd.conf.
> > > So my question is how can I make BIND9 add 'fixed-address' hosts 
to
> > > dhcp.leases? Looks like this is the only way to make BIND9 remove
> > > addresses from the zones file on DHCPRELEASE.
> 
> One way to do this "properly" is to "reserve" the addresses via
> assignments in the DHCP configuration.  This is done by taking the MAC
> address and "assigning" is to an IP address.
> 
> You get the flexibility of DHCP with the stability of a fixed address.
> 
> > >   
> > Even if you could coax your DHCP subsystem into generating these 
> Dynamic 
> > Updates, why would you constantly delete and re-add the same 
> > name/address associations? Seems like you're making your DNS 
> > infrastructure perform work for little or no benefit.
> > 
> > - Kevin

---------------------------------------------------------------------
Gregory Hicks                           | Principal Systems Engineer
Cadence Design Systems                  | Direct:   408.576.3609
555 River Oaks Pkwy M/S 9B1
San Jose, CA 95134

I am perfectly capable of learning from my mistakes.  I will surely
learn a great deal today.

"A democracy is a sheep and two wolves deciding on what to have for
lunch.  Freedom is a well armed sheep contesting the results of the
decision."

"The best we can hope for concerning the people at large is that they
be properly armed." --Alexander Hamilton