Dynamic IP address assignment

Thomas Chen tchen
Fri Sep 19 23:03:05 PDT 2003

on 9/19/03 7:28 PM, Jouni Malinen at jkmaline at cc.hut.fi wrote:

> On Fri, Sep 19, 2003 at 07:45:22PM -0400, thomas chen wrote:
>> i think you are refering to RFC3203
>> basically this is a mechanism for DHCP daemon to issue a FORCE command
>> to ask client to re-get the IP assignment, DNS etc
> This should not be necessary with IEEE 802.1X/RADIUS IP assignment
> because IEEE 802.1X authorization has to be completed before DHCP can be
> used. Thus, the AP already knows the assigned IP address before needing
> to reply to any DHCP requests. If RADIUS server decides to change the
> assigned address during re-authentication, this might be more relevant,
> but that does not sound like a common case.

actually, i have seen this quite a bit... here is a scenario...

CLIENT <--- WIFI ---> [HOSTAP + WAN INTERFACE] <------ WAN ---->

in many cases... CLIENT <----> connects to HOSTAP and do the
configuration (using some web interface) and then the other side
of BOX (WAN) connects to WAN...  if it is say cable modem or dsl
which gets assignment from some ISP, the box needs to push down
the DNS (probably not local ip assignment)...

the cleanest solution is for the client to get a force command to
go back and get DNS... but since many dhcp client do not have
that implemented... the user has to manually do something...

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