TTLS EAP “unsupported protocol” error

[Bill Schoolfield]

Trying to get Cambium 450 equipment to work with TTLS EAP and 
FreeRadius. Specifically FreeRadius 3.2.1 on Debian 12.5

Following all the information online, I’ve setup radius including 
creating my own certificates and tested the setup using the eapol_test 
tool. Results AOK.

But tests with the 450 Cambium equipment (20.1 firmware) fail at the ssl 
handshake with an error message in the log: “unsupported protocol”

I was able to get it to work by forcing TLS 1.0 (setting min and max TLS 
to 1.0 and setting cipher_list to DEFAULT at SECLEVEL=0). Obviously not a 
good thing to do but it does suggest a TLS version issue.

My question to the group is this simply a matter of what Cambium 
supports (TLS wise) or is it possible I have something wrong on the 
FreeRadius side?