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 From:  Melvin Backus <mbackus at bellsouth dot net>
 To:  Fred Wright <fw at well dot com>, m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] DHCP server - static clients only
 Date:  Wed, 23 Jun 2004 23:29:13 -0400
At 06:11 PM 6/23/2004, Fred Wright wrote:

>On Wed, 23 Jun 2004, Melvin Backus wrote:
> > At 05:36 PM 6/23/2004, Adam Nellemann wrote:
> > >Stefan Thuering wrote:
> > >
> > >>Is there a way to limit the DHCP server to work with static (known) mac
> > >>address clients only?
> > >>If I enter 4 static macs and limit the server to 4 addr. total it should
> > >>generally be ok, but if those clients aren't always running the free
> > >>slots can be snatched away. :(
> > >>A checkbox with "allow static clients only" would be cool !
> > >>p.s. m0n0wall is fantastic...
> > >>thanks
> > >>   Stefan
> > >
> > >I too would be interessted in this capability. I think one of the old 
> (pre
> > >1.0) betas were actually capable of doing static-only DHCP (not too sure
> > >though), simply by giving a dynamic IP range of x.x.x.0 to x.x.x.0,
> > >however, when I recently tested this, my host just got the x.x.x.0 IP
> > >address :(
>That's the trouble with having to specify it as a closed interval rather
>than a half-open interval. :-)
>What happens if you make .1 the minimum and .0 the maximum?
> > >
> > >This just to add my wote for the abovementioned checkbox. (or 
> something to
> > >similar effect?)
> > >
> > >Adam.
> >
> > Sounds like what you really want is an infinite length lease.
>No, because an infinite lease still doesn't let you *pick* the specific IP
>to be used.  Not to mention the fact that DHCP address asisgnments don't
>survive reboots on m0n0wall.
>                                         Fred Wright

So we're back to reservations?  That's what I always do and it's easy 
enough, although it's one thing to do it for a handful of machines but 
quite another to do for an entire /24 subnet.  I'm not sure I understand to 
part about picking specific IPs.  I thought they just wanted to have X 
machines which are always allowed to get leases, but anything else which 
happened to be connected would get rejected.  If that's the case, matching 
the number of machines to IPs works great as long as they always stay up, 
but his fear was that when one of them is offline something else could snag 
the IP.  A very valid point.  My question is I suppose, what happens if you 
do a 10  year lease, acquire an IP, turn off the machine, try to add a 
different machine to the network.  I'm guessing that the new machine won't 
get an address.  I see your point about leases not surviving reboots.  Does 
that apply only to the CD version or the generic-pc and soekris versions too?

Good, Fast, Cheap... Pick any two