Windows XP seems to *forget* to send DHCPINFORM and DHCPRELEASE

Michael Parker mike.parker at
Tue Apr 21 14:47:13 UTC 2009

On Tue, Apr 21, 2009 at 01:19:43AM -0500, michael kapelko wrote:
> When I turn PC off or turn connection off, Windows XP doesn't send
> DHCPRELEASE. Is this ok?

As I understand it, yes, this is OK.  DHCPRELEASE is only sent when you
want to give up the lease before its expiration and turning off the PC
doesn't necessarily mean you want to do this.  When this PC restarts, it
will see that it had an unexpired lease when it shutdown and will send a
DHCPREQUEST to confirm that it can still use it.  

> When I only provide IP, mask, router IP and DHCP service is on,
> Windows XP does not send DHCPINFORM to ask for DNS.

I believe DHCPINFORM is only used by clients that are not getting their
IP through DHCP.  If you are supplying the IP through DHCP then this
client will get the DNS option from the DHCPOFFER and DHCPACK messages.


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