blocking anonymous outer identity

[Riccardo Veraldi]

Hello,
I have some anonymous outer identity in the autentication log of freeradius.

I use freeradius version < 2.0 with EAP-TTLS and 802.1x on hte 
supplicant side.

how can I forbid users to use an anonymous identity or to use an outer 
identity
different from the real identity used for authentication/authorization ?
I want to force users to use their own real identity based on their real 
credentials
users at domainname without using an outer identity.

I want to forbid this because if users use anonymous outer identity in 
the freeradius
log I cannot see who is the user actually autenticating.

any hints about this problem of mine ?
thank you

Rick