OpenSSL must be installed to use either EAP-TLS, EAP-TTLS, or PEAP!
When using EAP-TLS, both the Authentication Server and all the Supplicants (clients) need certificates [RFC2459] . Using EAP-TTLS or PEAP, only the Authentication Server requires certificates; Supplicant certificates are optional.
You get certificates from the local certificate authority (CA). If there is no local CA available, OpenSSL may be used to generate self-signed certificates.
Included with the FreeRADIUS source are some helper scripts to generate self-signed certificates. The scripts are located under the scripts/ folder included with the FreeRADIUS source:
CA.all is a shell script that generates certificates based on some questions it ask. CA.certs generates certificates non-interactively based on pre-defined information at the start of the script.
The scripts uses a Perl script called CA.pl, included with OpenSSL. The path to this Perl script in CA.all and CA.certs may need to be changed to make it work.
More information on how to generate your own certificates can be found in the SSL certificates HOWTO.