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  • SAMFS's avatar
    SAMFS
    Copper Contributor
    Thanks for you quick reply! That is the document I referred to in my post. So, what's in there either does not answer my question or I got it wrong 😅
      • SAMFS's avatar
        SAMFS
        Copper Contributor

        By capturing the traffic to and from the server using Wireshark. The Exchange server contacted another SMTP host and after sending the STARTTLS command it sent the following cipher suites as part of the handshake:

        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
        TLS_RSA_WITH_AES_256_CBC_SHA
        TLS_RSA_WITH_3DES_EDE_CBC_SHA
        TLS_RSA_WITH_AES_128_CBC_SHA
        TLS_RSA_WITH_RC4_128_SHA
        TLS_RSA_WITH_RC4_128_MD5

        While the ciphers in the above registry key are as follows:

        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384
        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256
        TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P384
        TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P256
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P384
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P256
        TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P384
        TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P256
        TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P384
        TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P256
        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P384
        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P384
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P256
        TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P384
        TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P256
        TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P384
        TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P256
        TLS_RSA_WITH_AES_256_GCM_SHA384
        TLS_RSA_WITH_AES_128_GCM_SHA256

        Which matches the list from the best practice document.

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