Re: DHCP Lease Behaviour

From: Omar [MS] (omarm_at_online.microsoft.com)
Date: 01/07/05 

Date: Thu, 6 Jan 2005 18:15:07 -0800

Here is the expected behavior for Windows CE dhcp client. If the device is
moved from one network to another, DHCP will try to defend its lease first
by sending a REQUEST message and then by pinging the default gateway. If
that fails, it will start using an auto ip but periodically continue
checking availability of a DHCP server by sending DISCOVER messages. So,
ultimately it should detect the new DHCP server and try to obtain a lease.

By default the options requested from a server are subnet mask, domain name,
router, NB name server, NB node type, NB scope, and domain server.
Additional options can be requested/sent using DHCPOptions/DhcpSendOptions
registry key configurations. Configuring DhcpOptions override the default
parameter request list.

That said, if you are getting stuck on AutoIP, it might indicate that you
don't have a DHCP server on your customer's network or for some reason it is
not able to communicate with it properly. Do you have any network traces of
what is going on? 

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"Popoi" <Popoi@discussions.microsoft.com> wrote in message
news:D94A8261-89BB-40E1-BD6A-25BEE0382832@microsoft.com...
> Hello.
>
> We have a headless Windows CE Device that is connected as a DHCP client on
> customer's networks.
>
> The problem we have is that if you connect the device to our corporate
> network first, it will obtain all this lease information and an IP Address
> from our DHCP server with no problems.
>
> Now if you take that device and connect it to a customer's network, it
will
> try to continue its lease, but fail, and instead of automatically
releasing
> and renewing its old lease it will use the AutoIP Settings... OR sometimes
> even come up with the loopback address set.
>
> Is there a way to configure the CE image so that it doesn't obtain any
lease
> info other than just the IP, Subnet, Gateway, DNS. And will always renew
it's
> lease when rebooted? I was thinking of excluding those settings from the
> hive, and only allow IPAddress, SubnetMask, EnableDHCP, and DefaultGateway
to
> be nonvolatile but this solution seems a bit kludgy, it would be nice if
> Windows CE could be configured so that it just renewed its lease instead.
>
> (Using 4.20 by the way)
>
> Thanks all

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