Using ISE for guest access together with anchor controller WLC in DMZ

Question

Hi there,
I setup a guest WLAN in our LAB environment. I have one internal WLC connection to an anchor controller in our DMZ. I'm using the WLC integrated web-auth portal which works fine.
To gain more flexibility regarding guest account provisioning and reporting my idea is to use Cisco Identity Services Engine (ISE) for web-authentication. So the anchor controller in the DMZ would redirect the guest clients to the ISE portal.
As the ISE is located on the internal network while the guest clients end up in the DMZ network this would mean that I have to open the web-auth portal port of ISE for all guest client IPs in order to be able to authenticate.
Does anyone know of a better solution for this ? Where to place the ISE for this scenario, etc ?
Thx
Frank

Answer 1

So i ran into a similar scenario on a recent deployment:
We had the following:
WLC-A on private network (Inside)
ISE Servers ISE01 and ISE02 (Inside)
WLC-B Anchor in DMZ for Guest traffic (DMZ)
ISE Server 3 (DMZ)
ISE01 and ISE02 are used for 802.1X for the private network WLAN.
Customer does not allow guest traffic to move from a less secure network to a more secure network (Compliance reasons).
The foreign controller (WLC-A) must handle all L2 authentication and it must use the same policy node that the clients will hit for web auth.  Since we want to do CWA, we use Mac Filtering with ISE as the radius server.  If you send this traffic RADIUS authentication for Mac Filtering to ISE01/ISE02, it will use https://ise01.mydomain.com/... to redirect the client to.  Since we don't allow traffic to traverse from the DMZ with the anchor in it back inside to the network where ISE01 and ISE02 are, client redirection fails.  (This was a limitation of ISE 1.1.  Not sure if this persists in 1.2 or not.
So what now?  In our deployment we decided to use a 3rd ISE policy node (ISE03 in the DMZ) for guest authentiction from the Foreign controller so that the client will use a DNS of https://ise03.mydomain.com/... to redirect the client to.  Once the session is authenticated, ISE03 will send a CoA back to the foreign which will remove the redirect for the session.  Note, you do have to allow ISE03 to send a CoA.
In summary, if you can't allow guest traffic to head back inside the network to hit the CWA portal, you must add a policy node in a DMZ to use for the CWA portal so they have a resolvable and reachable policy node.