address pools

[Chris Miller]

Hi Simon,

THANKS THANKS THANKS THANK THANKS and yet again THANKS  for the comments.
:-)

I did discover classes and I'm aware that I can "allow" and "deny' members
of <class> in the pools, but it is not clear haw I assert that my hosts are
members of <class>.  The doc show lots of ways to interrogate options that
are already there but I'm hoping I can do something like:

	Host trax {hardware ethernet XX:XX:XX:XX:XX:XX; class "servers"' } 

... or even 

	Host trax {hardware ethernet XX:XX:XX:XX:XX:XX; class "servers"';
class "static"; class "infrastructure"} 

... but I've found nothing that hints at this.  Google was no help either.
This was why I thought if I declared my host in the scope of the pool, that
their address would be allocated from that pool -- not really so silly, you
see.  And the docs are quiet good at one level, but there is a larger
context that is not clear -- as evidenced by some of my confusion.  All the
statements and options are clearly explained but the higher level discussion
of how to assemble them to achieve certain goals is not at all clear.
Unless I'm reading the wrong docs ...  ?

About the statically configured gw1 -- you're right.  Gw1 is a router and I
have it in dhcpd.conf for documentation purposes, it is not a dhcp client.
I don't want to go moving things around in dhcpd.conf and forget about the
non-dhcp participants -- so I included them in the file as though they were
in fact clients.  My hope is that I will not accidentally re-lease an
already assigned address and that dhcpd will alert me if I forget.  This is
part of the reason I want to be able to classify the elements of my network
-- they have different behaviors, not just simply with respect to dhcp, but
generally.

Chris.

Fill what's empty, empty what's full, and scratch where it itches.
Life is a journey, not a destination ...







> -----Original Message-----
> From: dhcp-users-bounce at isc.org 
> [mailto:dhcp-users-bounce at isc.org] On Behalf Of Simon Hobson
> Sent: Thursday, November 16, 2006 12:07 AM
> To: dhcp-users at isc.org
> Subject: Re: address pools
> 
> >I read the docs for dhcpd.conf and I am apparently still confused.
> 
> Yes, I believe you are.
> 


> >Don't the known host get leases from the pool where they are known?
> 
> NO NO NO NO NO and yet again NO
> 


> >Can anybody offer advice?
> 
> Yes, you need to use classes. Assign devices to classes, then 
> use "allow members of ..." in the pools. Take another look at 
> man dhcpd.conf and see the section on classing, then come 
> back if there is anything you don't understand.
> 
> 
> As a general network design comment, I see that you have a 
> host labelled "gw1" which I'm guessing is your router. If 
> this is your default router then I would strongly suggest 
> statically configuring it - it's just too fundamental to the 
> operation of your network to have it waiting for your dhcp 
> server to come up - especially when you dhcp server will be 
> relying on it to be there and working for it to start.
> 
> For the same reason, I would not consider running a dhcp 
> server on a machine that wasn't statically configured for 
> everything the dhcp server needs (network, default gateway, 
> dns, and a few other).
>