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 From:  Ian Cartwright <ian351c at cox dot net>
 To:  "M. G. (Michael) de Bruin" <mg dot debruin at buum dot nl>
 Cc:  Bart Smit <bit at pipe dot nl>, Manuel Kasper <mk at neon1 dot net>, Michael Willers <splasher at gmx dot ch>, m0n0wall at lists dot m0n0 dot ch, m0n0wall dash dev at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall-dev] Re: [m0n0wall] dhpc lease list issue
 Date:  Fri, 02 Jan 2004 16:47:56 -0700
On Fri, 2004-01-02 at 15:45, M. G. (Michael) de Bruin wrote:
> Bart Smit wrote:
> 
> > Hi Manuel & lists (cc-ing -dev),
> > 
> >> m0n0wall loses the DHCP lease database on reboot - this is a design 
> >> choice.
> > 
> > 
> > After actually digging up and reading the relevant RFC (2131), I feel 
> > the need to reiterate my previously stated point that this is a bad 
> > design choice. It conflicts with an explicit design goal of the DHCP 
> > mechanism. To quote:
> > 
> >  > The following list gives design goals specific to the transmission of
> >  > the network layer parameters.  DHCP must:
> > [...]
> >  >     o Retain DHCP client configuration across server reboots, and,
> >  >       whenever possible, a DHCP client should be assigned the same
> >  >       configuration parameters despite restarts of the DHCP mechanism,
> > 
> > I really feel this leaves no room for slack (apart from the fact that 
> > I'm one of those rare folks that is actually bitten by the loss of state) .
> > 
> > Will a big "please" do? :-)
> > 
> > --Bart
> > 
> > 
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> > 
> 
> I think you are going to have added cost as soon as you implement this: 
> especially with a short lease time, your CF will wear out very soon.
> 
> But: is it possible to use an NFS mount for these kind of things? If you 
> really need it you probably don't mind setting up another server w/ NFS 
> (eh... am I the only geek with to many servers? :)). Or, is this too 
> far-fetched?
> 
> Anyway, just a thought.
> 
> Michael
> 
> 

Or, how about this: keep the dhcp.leases file in memory (probably in
/var/etc, which is where it is kept today, I presume) and save it to
flash whenever the system is rebooted (using the M0n0wall equivalent of
rc.shutdown). This would save wear and tear on any CF while giving lease
information across (graceful) reboots.

Cheers,

Ian