How does hostapd interact with an external RADIUS server?

[Jouni Malinen]

On Thu, Jul 14, 2011 at 07:52:56AM -0500, Harshal Chhaya wrote:
> My understanding is that the RADIUS server is used only during
> authentication and then for re-keying but is out of the picture during
> normal data transfer.

Correct or well, not all re-keying cases require RADIUS authentication
either.

> I am curious what happens if the freeRADIUS server dies. Does hostapd
> (somehow) disassociate all clients who then have to re-connect and
> re-authenticate?

hostapd does not even know that the RADIUS server died until there is a
need for a new authentication.. No clients are disconnect or forced to
re-authenticate in case of RADIUS issues.

> I am seeing clients dropping off the network around the same time the
> freeRADIUS server is dying (still investigating that problem) and I am
> curious about the connection between the two events.

You should be able to find more details on what happened from the
hostapd debug log, but unless you've configured the system to require
frequent re-authentication with the RADIUS server, there should not
really be any connection between these two events as far as clients that
had already successfully connected to the network are concerned.

-- 
Jouni Malinen                                            PGP id EFC895FA