Understanding the IP Pool module

[Phil Mayers]

On 02/13/2013 07:23 AM, Бен Томпсон wrote:

> One thing I still don't understand though is how best to use ippool
> for DHCP. I don't understand where and how I should call the module
> during a DHCP transaction. For example I can call it during
> DHCP-Discover, but it seems that if I call it again during
> DHCP-Request I might get different address even when the key is the
> same. I will continue to to study the code to see why this happens and
> if I figure it out I will report back with my findings.

With difficulty, in short.

The ippool module is old, and predates the DHCP functionality. You would 
need to "fake up" some RADIUS attributes in the DHCP packet, then ensure 
that ippool is called in a manner that hands out IPs correctly. This may 
prove to be impossible.

There is an example of doing this with the sqlippool module, which is 
rather better suited to this; by customising the queries you can ensure 
that different IPs in DISCOVER/REQUEST are not a problem. See the GIT 
repo for details:

https://github.com/FreeRADIUS/freeradius-server/blob/master/raddb/policy.d/dhcp

https://github.com/FreeRADIUS/freeradius-server/blob/master/raddb/mods-available/dhcp_sqlippool