With some notes I wrote on the subject a few years ago when I couldn't work it out
http://notes.asd.me.uk/2012/04/20/where-is-the-challenge-in-eap-ttls-ms-chap...
So my uneducated guess is that rad_eap_test is sending an incorrect challenge. Are you setting chap-challenge or ms-chap-challenge manually, which for EAP-TTLS should be generated from the SSL keying data.
Ok, it turns out it was user error... I return you to your regular programming. :-) Sorry for the interruption. Stefan Paetow Moonshot Industry & Research Liaison Coordinator t: +44 (0)1235 822 125 gpg: 0x3FCE5142 xmpp: stefanp@jabber.dev.ja.net skype: stefan.paetow.janet Lumen House, Library Avenue, Harwell Oxford, Didcot, OX11 0SG jisc.ac.uk Jisc is a registered charity (number 1149740) and a company limited by guarantee which is registered in England under Company No. 5747339, VAT No. GB 197 0632 86. Jisc’s registered office is: One Castlepark, Tower Hill, Bristol, BS2 0JA. T 0203 697 5800. Jisc Collections and Janet Ltd. is a wholly owned Jisc subsidiary and a company limited by guarantee which is registered in England under Company No. number 2881024, VAT No. GB 197 0632 86. The registered office is: Lumen House, Library Avenue, Harwell, Didcot, Oxfordshire, OX11 0SG. T 01235 822200.