hostapd and load balancers

[Shwe Toe]

Hi,

I have some radius servers behind a Nginx load balancer. I have
configured Nginx to route egress traffic from upstream radius servers
directly to access points (bypassing the load balancer). In the AP's
hostapd.conf, "auth_server_addr" is set to load balancer. There is no
secondary auth_server_addr. I have two APs from different vendors and
noticed that hostapd behaves differently with this setup.

On both APs, Radius Access-Request will send to the load balancer
(192.168.1.2), and receive Access-Challenge from upstream radius
server (192.168.1.99).

One AP sends the next Access-Request to load balancer (192.168.1.2).
Another AP sends the next Access-Request to the upstream radius server
(192.168.1.99).

What should be the correct behavior for hostapd? Where should it send
the next Access-Request?

Thanks,
Nyan