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 From:  Melvin <melvin at sleepydragon dot net>
 To:  Manuel Kasper <mk at neon1 dot net>
 Cc:  Frederick Page <fpage at thebetteros dot oche dot de>, m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] Half second "feature" is also in DHCP server
 Date:  Sun, 20 Mar 2005 15:58:30 -0500
Manuel Kasper wrote:

>On 20.03.2005 18:25 +0100, Frederick Page wrote:
>
>  
>
>>>One can see that clearly when remote logging to a linux-machine,
>>>whose dhcp-client indicates the renewal intervals in syslog.
>>>      
>>>
>>Addition: you can see it even on a Win client: ipconfig /all shows
>>when lease expires. All values in DHCP server 1.2b6 are divided by
>>two. I know this is only a minor issue, this might be a "to do" for
>>next beta release?
>>    
>>
>
>AFAIK it's normal (and even in the DHCP RFC) that DHCP clients renew
>their lease after half of the lease time has elapsed (use Ethereal on
>the DHCP ACKs and you'll find that the lease time reflects what you
>set in the webGUI, or 2 hours by default), so we don't need to (and
>won't) change anything in m0n0wall here.
>
>- Manuel
>  
>
Requesting a renewal and lease expiration are not the same thing.  If 
you set a lease expiration of 7 days, the client will request renewal 
after 3.5 days, but it will continue to use the existing IP until a) it 
expires, b) the renewal request is denied and the offered address 
changes. Given that no other machine should have that IP, there would be 
no reason for b, however if you take the client machine offline for 5 
days after receiving an IP, it should still be valid and available up 
until the expiration specified.  It sounds like in the current 
implementation that IP address would be flagged as stale and subject for 
recovery after only 3.5 days instead.  If I've misunderstood what's 
actually happening then my apologies, but it certainly sounds like it's 
broken.


-- 
Whom computers would destroy they must first drive mad.