Windows leases through a PC reset

Thu May 10 19:34:15 UTC 2007

Simon - curious what Windows OS on the PC was in play during your test ?
Thanks for the good feedback.

>>> Simon Hobson <dhcp1 at> 5/10/2007 3:16 PM >>>
I wrote:

>I'm curious now, I'll check tomorrow !

OK, it wasn't 'tomorrow, but I've had a look and this is what I found 
with the dhcp server turned off (t=0 is when the first packet is 
logged) :

PC does three DHCP Requests, at t=0, t=4s, and t=13s

At t=28s to t=30s it does three Gratuitous ARP broadcasts for it's 
previous IP address (thus checking for anything else using the 

It then does an ARP request for the router and gets a reply.

After that it starts using the address and there's a pile of NBNS 
packets and over the next minute or two it elects itself as Master 
Browser (it's the only Windoze system on the network).

So that seems quite reasonable. The dhcp server cannot be reached but 
the client has a valid lease, nothing else is using the address, and 
the router is the same as last time - thus it should be safe to carry 
on using the address.

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