Hi, 802.1x Authentication with EAP-TLS, works perfectly with a Centos client, however not from a Cisco IP Phone. Basic Specs For Server; * Centos 7.2 x64 * freeradius-3.0.11 * Communicating through a Dell N3000 switch. * Cisco 7945 IP Phone I'm just after advice on how to solve the "certificate signature failure" error? Error: (3) eap_tls: Creating attributes from certificate OIDs (3) eap_tls: TLS-Cert-Serial := "01" (3) eap_tls: TLS-Cert-Expiration := "190622025857Z" (3) eap_tls: TLS-Cert-Subject := "/CN=ios-ca" (3) eap_tls: TLS-Cert-Issuer := "/CN=ios-ca" (3) eap_tls: TLS-Cert-Common-Name := "ios-ca" (3) eap_tls: Creating attributes from certificate OIDs (3) eap_tls: TLS-Client-Cert-Serial := "02" (3) eap_tls: TLS-Client-Cert-Expiration := "190622025857Z" (3) eap_tls: TLS-Client-Cert-Subject := "/CN=SEP20BBC092DE1D" (3) eap_tls: TLS-Client-Cert-Issuer := "/CN=ios-ca" (3) eap_tls: TLS-Client-Cert-Common-Name := "SEP20BBC092DE1D" ---> (3) eap_tls: ERROR: SSL says error 7 : certificate signature failure <------- (3) eap_tls: >>> send TLS 1.0 Alert [length 0002], fatal decrypt_error (3) eap_tls: ERROR: TLS Alert write:fatal:decrypt error tls: TLS_accept: Error in SSLv3 read client certificate B (3) eap_tls: ERROR: SSL says: error:0D0C50A1:asn1 encoding routines:ASN1_item_verify:unknown message digest algorithm (3) eap_tls: ERROR: SSL_read failed inside of TLS (-1), TLS session failed (3) eap_tls: ERROR: TLS receive handshake failed during operation (3) eap_tls: ERROR: [eaptls process] = fail (3) eap: ERROR: Failed continuing EAP TLS (13) session. EAP sub-module failed Regards, Craig