"I'm new to freeradius and it appears to be working but connections are not always successful. I have noticed the below issues with the certificates im using, i think due them not being in a chain including the intermediate cert. However i don't think this is causing the intermittent connection issue. Can anyone suggest anything? Certificate chain - 2 cert(s) untrusted (TLS) untrusted certificate with depth [1] subject name /DC=local/DC=universe/CN=Universe Issuing CA (TLS) untrusted certificate with depth [0] subject name /CN=xxxxxxxxxxxxxxxxxxx.local " Hi, In freeradius, the certificate is checked by calls to openssl, specifically it is defined in the default configuration in the eap module, section tls- config. The custom call is client = "/usr/bin/openssl verify -CApath ${..ca_ path} %{TLS-Client-Cert-Filename}". Since you have the CA chain listed in one file, it won't work because you have verification with a reference to the CA path in the definition. Try saving CA-root and CA-intermediate as separate files in ca_path (default /etc/freeradius/certs) and then create hash symlinks - see: cd /etc/freeradius/certs c_rehash . and then restart freeradius. Regards, Petr L.