RADIUS CoA - verifying users being online.

RouterOS General
1

What combination of RADIUS Attributes (fit for CoA/Incoming) makes RouterOS (v7.18.2) respond, via “Incoming” aka CoA aka port 3799, with Error-Cause = Session-Context-Not-Found (503) ?

I want to let Emerald (6) (https://www.iea-software.com) detect if my PPPoE and Hotspot users, who are no longer logged in, be detected so Emerald doesn’t think users aren’t connected 100 times. The detection method Emerald uses is CoA requests, and only if RouterOS replies with; Error-Cause = Session-Context-Not-Found (503) - will the session be considered dead/stale by Emerald.

So what combination of attributes will let RouterOS respond properly? I feel like its either responding with COA-OK or COA-NAK with 406 “Unsupported Extension”, and that seems to be the only responses i can possibly get.

2

We validate the user status using the accounting requests, I don’t know if its the best way but it works so well for us:

$pppoe_status = $request->input('Acct-Status-Type');

if ($pppoe_status === 'Stop') {
    $updates['last_ip_address'] = null;
    $updates['pppoe_status'] = 'disconnected;
}
3

The problem is that over time, the accounting records are lost (someone logs off while upstream is down, RADIUS server will think session is still going, but PPPoE server wont say anything to RADIUS server because session is long since dead and stop records were sent while link was down). This is why we need methods to verify sessions.

Basically the CoA request method is asking the PPPoE/Hotspot server to Change something about the PPPoE/Hotspot session, but it doesn’t ask for any real change. It just wants to know, do you know of this session? And if i could get RouterOS to respond with the proper error message (Session-Context-Not-Found), then RADIUS server will know that (basically) “This session no longer exists, i have no idea what session you are talking about”.