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 From:  =?iso-8859-1?Q?Bj=F6rn?= =?iso-8859-1?Q?_P=E5lsson?= <bjorn at networksab dot com>
 To:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] dhpc lease list issue
 Date:  Sat, 03 Jan 2004 00:34:31 +0100
At 23:45 2004-01-02 +0100, you 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 
>Anyway, just a thought.
I would say that the gains of letting a computer get the same IP after a
reboot (that is extremely rare (uptime average fo my servers is >150 days))
on a NAT-ed network is zero to none. Crashing a CF for that is not smart.
If you deal with some servers, then put them in a static list or just skip
the DHCP for them.

For my m0n0 I am setting up, I will have public IP for everybody behind it
but I don't care jack shit if they get another IP after I reboot the
router. The rotationrate of IP's on my network is about 7 days anyway.
Sometimes in weekends, 2 days. That means if you make a quick trip to your
grannie, you'll certainly have a new IP on monday morning. With 400+
customers on two class C nets, this happens.

I bet none of you are going to use a m0n0 to serve a net as big as this!?

// Björn