Host options and DCHP-Inform

Friesen, Don CITZ:EX Don.Friesen at gov.bc.ca
Wed Mar 20 14:31:42 UTC 2013


>On Behalf Of Simon Hobson
>Sent: Wednesday, March 20, 2013 7:08 AM

>Leaving aside the inference that a device which got an address by DHCP shgouldn't then use DHCP Inform, I do think that Microsoft's approach is architecturally the right thing to do.
>If you consider the DHCP client as a service, then other parts of the OS or userland software can use it to get config. The DHCP client itself should handle/know about as little as possible. So while the network code asks the DCHP client to get an address etc which is part of the basic setup - getting config for other software shouldn't (IMO) really be considered part of that. So when the user starts a web browser, it would seem reasonable to me for the browser to ask the DCHP service to see if it can get certain options for it - at which point the DHCP Inform is sent.


However, the DHCPINFORM, send on behalf of the Web Browser, should not change the options that the network code obtained during lease acquisition.  The Default Gateway and DNS servers supplied to a statically reserved machine could be different than the dynamic pool.  Indeed, that is what we have in numerous locations.  The DHCPINFORM rewrites that causing the client workstation to lose access to the path and services it requires.

Don.


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