13. Security Considerations

13. Security Considerations

The Diameter base protocol messages SHOULD be secured by using TLS [RFC5246] or DTLS/SCTP [RFC6083]. Additional security mechanisms such as IPsec [RFC4301] MAY also be deployed to secure connections between peers. However, all Diameter base protocol implementations MUST support the use of TLS/TCP and DTLS/SCTP, and the Diameter protocol MUST NOT be used without one of TLS, DTLS, or IPsec.

If a Diameter connection is to be protected via TLS/TCP and DTLS/SCTP or IPsec, then TLS/TCP and DTLS/SCTP or IPsec/IKE SHOULD begin prior to any Diameter message exchange. All security parameters for TLS/TCP and DTLS/SCTP or IPsec are configured independent of the Diameter protocol. All Diameter messages will be sent through the TLS/TCP and DTLS/SCTP or IPsec connection after a successful setup.

For TLS/TCP and DTLS/SCTP connections to be established in the open state, the CER/CEA exchange MUST include an Inband-Security-ID AVP with a value of TLS/TCP and DTLS/SCTP. The TLS/TCP and DTLS/SCTP handshake will begin when both ends successfully reach the open state, after completion of the CER/CEA exchange. If the TLS/TCP and DTLS/SCTP handshake is successful, all further messages will be sent via TLS/TCP and DTLS/SCTP. If the handshake fails, both ends MUST move to the closed state. See Section 13.1 for more details.