Hello,
I'm currently on the first phases of deploying a Cisco IPT 802.1X based proof of concept using freeradius, Cisco switching infrastructure (4500's).
The requirements are to use EAP-TLS authentication for the phones, and freeradius as Radius Server.
While trying out the concept in lab using an ISE Radius server, the configuration was straightforward and I did manage to authenticate IP phones using their MIC certificates to the ISE.
Going to actual testing with freeradius, EAP-TLS authentication keeps looping, the phones keep sending RADIUS Access requests, but not being rejected or allowed.
What was done:
- set up freeradius with EAP-TLS configuration, trusting both cisco CA root and manufacturing root.
- freeradius has a server certificate generated by Thawte SSL CA certificate, where EKU fields are properly set for server authentication (and also client authentication)
- Phone had 802.1X enabled (and it does support EAP-TLS, as verified with the ISE test)
What I can see while running a wireshark trace on freeradius is:
- both parties negotiate properly that they will engage in EAP-TLS.
- they start the TLS handshake
- Server sends its certificate on a Server Hello to the phone (which is meant to not validate it)
- Client (phone) never sends its certificate (MIC) to the server.
- Client restarts EAP-TLS negotiation and goes on and on.
Unfortunately the debugs/Captures on freeradius do not allow to verify if the server certificate exchange is finished, or if it is failing somewhere (like a fragment being dropped).
Does anyone have an idea on what might be happening? I find it very strange that the phone, on a freeradius deployment, would behave differently than one on a ISE deployment, especially because it doesn't validate the server certificate, so it shouldn't matter what is presented to the phone.
Phone firmware is 9.2(3) and callmanager 8.6
Thanks
Gustavo Novais
