diff --git a/ChangeLog b/ChangeLog
index 265205cdb..474dcd0fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
-mbed TLS 2.x.x branch released xxxx-xx-xx
+= mbed TLS 2.x.x branch released xxxx-xx-xx
 
 Security
 
@@ -12,6 +12,14 @@ Bugfix
    * Remove invalid use of size zero arrays in ECJPAKE test suite.
    * Fix insufficient support for signature-hash-algorithm extension,
      resulting in compatibility problems with Chrome. Found by hfloyrd. #823
+   * If sending a fatal alert fails, make sure not to hide the error
+     that triggered the alert.
+   * In SSLv3, if refusing a renegotiation attempt, don't process any further
+     data.
+
+Changes
+   * Send fatal alerts in many more cases instead of dropping the connection.
+
 
 = mbed TLS 2.5.0 branch released 2017-05-17
 
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index fcc7f5ff1..616cadc08 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -264,11 +264,12 @@ static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECP_C)
     for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ )
-    {
-        info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
 #else
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
+#endif
     {
+#if defined(MBEDTLS_ECP_C)
+        info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
 #endif
         if( info == NULL )
         {
@@ -289,11 +290,12 @@ static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECP_C)
     for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ )
-    {
-        info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
 #else
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
+#endif
     {
+#if defined(MBEDTLS_ECP_C)
+        info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
 #endif
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
@@ -1055,8 +1057,6 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
 {
-    int ret;
-
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
     {
@@ -1069,10 +1069,8 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
                           ssl->peer_verify_data, ssl->verify_data_len ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
-
-            if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                return( ret );
-
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
         }
     }
@@ -1082,10 +1080,8 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
         if( len != 1 || buf[0] != 0x00 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
-
-            if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                return( ret );
-
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
         }
 
@@ -1108,6 +1104,9 @@ static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
         len != 1 ||
         buf[0] != ssl->conf->mfl_code )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching max fragment length extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1123,6 +1122,9 @@ static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
     if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED ||
         len != 0 )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching truncated HMAC extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1143,6 +1145,9 @@ static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
         ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ||
         len != 0 )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching encrypt-then-MAC extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1163,6 +1168,9 @@ static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
         ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ||
         len != 0 )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching extended master secret extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1182,6 +1190,9 @@ static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
     if( ssl->conf->session_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED ||
         len != 0 )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching session ticket extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1206,6 +1217,8 @@ static int ssl_parse_supported_point_formats_ext( mbedtls_ssl_context *ssl,
     if( list_size + 1 != len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1217,7 +1230,7 @@ static int ssl_parse_supported_point_formats_ext( mbedtls_ssl_context *ssl,
         {
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
             ssl->handshake->ecdh_ctx.point_format = p[0];
-#endif            
+#endif
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
             ssl->handshake->ecjpake_ctx.point_format = p[0];
 #endif
@@ -1230,6 +1243,8 @@ static int ssl_parse_supported_point_formats_ext( mbedtls_ssl_context *ssl,
     }
 
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "no point format in common" ) );
+    mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                    MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
     return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
 }
 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || 
@@ -1258,6 +1273,8 @@ static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
                                                 buf, len ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( ret );
     }
 
@@ -1274,7 +1291,12 @@ static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
 
     /* If we didn't send it, the server shouldn't send it */
     if( ssl->conf->alpn_list == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching ALPN extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
 
     /*
      * opaque ProtocolName<1..2^8-1>;
@@ -1288,15 +1310,27 @@ static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
 
     /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
     if( len < 4 )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
 
     list_len = ( buf[0] << 8 ) | buf[1];
     if( list_len != len - 2 )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
 
     name_len = buf[2];
     if( name_len != list_len - 1 )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
 
     /* Check that the server chosen protocol was in our list and save it */
     for( p = ssl->conf->alpn_list; *p != NULL; p++ )
@@ -1309,6 +1343,9 @@ static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
         }
     }
 
+    MBEDTLS_SSL_DEBUG_MSG( 1, ( "ALPN extension: no matching protocol" ) );
+    mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                    MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
     return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
 }
 #endif /* MBEDTLS_SSL_ALPN */
@@ -1413,6 +1450,7 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 
     if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
     {
+        /* No alert on a read error. */
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
     }
@@ -1438,6 +1476,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 #endif /* MBEDTLS_SSL_RENEGOTIATION */
 
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -1464,6 +1504,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         buf[0] != MBEDTLS_SSL_HS_SERVER_HELLO )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1518,6 +1560,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
     if( n > 32 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1530,6 +1574,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
             ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) + 40 + n + ext_len )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
         }
     }
@@ -1540,6 +1586,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
     else
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1567,6 +1615,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 #endif/* MBEDTLS_ZLIB_SUPPORT */
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "server hello, bad compression: %d", comp ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
     }
 
@@ -1578,6 +1628,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
     if( ssl->transform_negotiate->ciphersuite_info == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "ciphersuite info for %04x not found", i ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
@@ -1615,6 +1667,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
             return( ret );
         }
     }
@@ -1634,6 +1688,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -1645,6 +1701,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         if( ssl->conf->ciphersuite_list[ssl->minor_ver][i] == 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
         }
 
@@ -1662,6 +1720,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
       )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
     ssl->session_negotiate->compression = comp;
@@ -1680,6 +1740,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         if( ext_size + 4 > ext_len )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
         }
 
@@ -1850,9 +1912,8 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 
     if( handshake_failure == 1 )
     {
-        if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-            return( ret );
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
 
@@ -2218,6 +2279,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ( ret = ssl_get_ecdh_params_from_cert( ssl ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "ssl_get_ecdh_params_from_cert", ret );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( ret );
         }
 
@@ -2239,6 +2302,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -2256,6 +2321,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         }
 
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -2272,6 +2339,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ssl_parse_server_psk_hint( ssl, &p, end ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
     } /* FALLTROUGH */
@@ -2293,6 +2362,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ssl_parse_server_dh_params( ssl, &p, end ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
     }
@@ -2309,6 +2380,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ssl_parse_server_ecdh_params( ssl, &p, end ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
     }
@@ -2324,6 +2397,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ret != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
     }
@@ -2354,12 +2429,16 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
                                                &md_alg, &pk_alg ) != 0 )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
                 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
             }
 
             if( pk_alg != mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ) )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
                 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
             }
         }
@@ -2391,6 +2470,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( end != p + sig_len )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
 
@@ -2462,6 +2543,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
                                      mbedtls_md_info_from_type( md_alg ), 0 ) ) != 0 )
             {
                 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
                 return( ret );
             }
 
@@ -2485,6 +2568,8 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ssl->session_negotiate->peer_cert == NULL )
         {
             MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
         }
 
@@ -2494,12 +2579,16 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
         }
 
         if( ( ret = mbedtls_pk_verify( &ssl->session_negotiate->peer_cert->pk,
                                md_alg, hash, hashlen, p, sig_len ) ) != 0 )
         {
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR );
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
             return( ret );
         }
@@ -2562,6 +2651,8 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
         if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
             return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
         }
 
@@ -2615,6 +2706,8 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
     if( ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
     }
 
@@ -2640,6 +2733,8 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
         if( ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
         }
     }
@@ -2653,6 +2748,8 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
     if( ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
     }
 
@@ -2689,6 +2786,8 @@ static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl )
         ssl->in_msg[0] != MBEDTLS_SSL_HS_SERVER_HELLO_DONE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello done message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO_DONE );
     }
 
@@ -3169,6 +3268,8 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -3186,6 +3287,8 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
         ssl->in_hslen < 6 + mbedtls_ssl_hs_hdr_len( ssl ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET );
     }
 
@@ -3199,6 +3302,8 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
     if( ticket_len + 6 + mbedtls_ssl_hs_hdr_len( ssl ) != ssl->in_hslen )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET );
     }
 
@@ -3224,6 +3329,8 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
     if( ( ticket = mbedtls_calloc( 1, ticket_len ) ) == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "ticket alloc failed" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
         return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
     }
 
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 5313bca1a..a61ff5f2d 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -101,6 +101,8 @@ static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
     if( servername_list_size + 2 != len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -111,6 +113,8 @@ static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
         if( hostname_len + 3 > servername_list_size )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
         }
 
@@ -135,6 +139,8 @@ static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
     if( servername_list_size != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -146,8 +152,6 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
 {
-    int ret;
-
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
     {
@@ -158,10 +162,8 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
                           ssl->verify_data_len ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
-
-            if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                return( ret );
-
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
         }
     }
@@ -171,10 +173,8 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
         if( len != 1 || buf[0] != 0x0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
-
-            if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                return( ret );
-
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
         }
 
@@ -216,6 +216,8 @@ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
         sig_alg_list_size % 2 != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -282,6 +284,8 @@ static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
         list_size % 2 != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -289,6 +293,8 @@ static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
     if( ssl->handshake->curves != NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -299,7 +305,11 @@ static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
         our_size = MBEDTLS_ECP_DP_MAX;
 
     if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
         return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+    }
 
     ssl->handshake->curves = curves;
 
@@ -332,6 +342,8 @@ static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
     if( list_size + 1 != len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -377,6 +389,8 @@ static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
                                                 buf, len ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( ret );
     }
 
@@ -395,6 +409,8 @@ static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
     if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -412,6 +428,8 @@ static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
     if( len != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -432,6 +450,8 @@ static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
     if( len != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -455,6 +475,8 @@ static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
     if( len != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -566,11 +588,19 @@ static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
 
     /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
     if( len < 4 )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+    }
 
     list_len = ( buf[0] << 8 ) | buf[1];
     if( list_len != len - 2 )
+    {
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+    }
 
     /*
      * Use our order of preference
@@ -584,13 +614,21 @@ static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
         {
             /* If the list is well formed, we should get equality first */
             if( theirs > end )
+            {
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+            }
 
             cur_len = *theirs++;
 
             /* Empty strings MUST NOT be included */
             if( cur_len == 0 )
+            {
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
+            }
 
             if( cur_len == ours_len &&
                 memcmp( theirs, *ours, cur_len ) == 0 )
@@ -873,10 +911,8 @@ static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
     if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
-
-        if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-            return( ret );
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 #endif /* MBEDTLS_SSL_RENEGOTIATION */
@@ -1022,9 +1058,8 @@ static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
                                     "during renegotiation" ) );
 
-                if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                    return( ret );
-
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
 #endif /* MBEDTLS_SSL_RENEGOTIATION */
@@ -1062,11 +1097,9 @@ static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
     ciphersuite_info = NULL;
 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
     for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
-    {
         for( i = 0; ciphersuites[i] != 0; i++ )
 #else
     for( i = 0; ciphersuites[i] != 0; i++ )
-    {
         for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
 #endif
         {
@@ -1084,7 +1117,6 @@ static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
             if( ciphersuite_info != NULL )
                 goto have_ciphersuite_v2;
         }
-    }
 
     if( got_common_suite )
     {
@@ -1111,10 +1143,8 @@ have_ciphersuite_v2:
         ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
-
-        if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-            return( ret );
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -1127,6 +1157,9 @@ have_ciphersuite_v2:
 }
 #endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
 
+/* This function doesn't alert on errors that happen early during
+   ClientHello parsing because they might indicate that the client is
+   not talking SSL/TLS at all and would not understand our alert. */
 static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
 {
     int ret, got_common_suite;
@@ -1170,6 +1203,7 @@ read_record_header:
     {
         if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
         {
+            /* No alert on a read error. */
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
             return( ret );
         }
@@ -1182,7 +1216,7 @@ read_record_header:
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM )
 #endif
         if( ( buf[0] & 0x80 ) != 0 )
-            return ssl_parse_client_hello_v2( ssl );
+            return( ssl_parse_client_hello_v2( ssl ) );
 #endif
 
     MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_hdr_len( ssl ) );
@@ -1422,10 +1456,8 @@ read_record_header:
                             " [%d:%d] < [%d:%d]",
                             ssl->major_ver, ssl->minor_ver,
                             ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
-
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                      MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
-
         return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
     }
 
@@ -1453,6 +1485,8 @@ read_record_header:
         sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -1476,6 +1510,8 @@ read_record_header:
         if( cookie_offset + 1 + cookie_len + 2 > msg_len )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
         }
 
@@ -1508,6 +1544,7 @@ read_record_header:
             /* We know we didn't send a cookie, so it should be empty */
             if( cookie_len != 0 )
             {
+                /* This may be an attacker's probe, so don't send an alert */
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
@@ -1532,6 +1569,8 @@ read_record_header:
         ( ciph_len % 2 ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -1550,6 +1589,8 @@ read_record_header:
         comp_len + comp_offset + 1 > msg_len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -1588,6 +1629,8 @@ read_record_header:
             if( msg_len < ext_offset + 2 )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
 
@@ -1598,6 +1641,8 @@ read_record_header:
                 msg_len != ext_offset + 2 + ext_len )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
         }
@@ -1617,6 +1662,8 @@ read_record_header:
             if( ext_size + 4 > ext_len )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
             switch( ext_id )
@@ -1763,6 +1810,8 @@ read_record_header:
             if( ext_len > 0 && ext_len < 4 )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
         }
@@ -1826,10 +1875,8 @@ read_record_header:
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
                                             "during renegotiation" ) );
-
-                if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                    return( ret );
-
+                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
                 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
             }
 #endif
@@ -1873,9 +1920,8 @@ read_record_header:
 
     if( handshake_failure == 1 )
     {
-        if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-            return( ret );
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
     }
 
@@ -1889,11 +1935,9 @@ read_record_header:
     ciphersuite_info = NULL;
 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
     for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
-    {
         for( i = 0; ciphersuites[i] != 0; i++ )
 #else
     for( i = 0; ciphersuites[i] != 0; i++ )
-    {
         for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
 #endif
         {
@@ -1910,19 +1954,20 @@ read_record_header:
             if( ciphersuite_info != NULL )
                 goto have_ciphersuite;
         }
-    }
 
     if( got_common_suite )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
                             "but none of them usable" ) );
-        mbedtls_ssl_send_fatal_handshake_failure( ssl );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
     }
     else
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
-        mbedtls_ssl_send_fatal_handshake_failure( ssl );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
         return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
     }
 
@@ -3425,13 +3470,8 @@ static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned cha
     if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
     {
         MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
-        if( ( ret = mbedtls_ssl_send_alert_message( ssl,
-                              MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                              MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY ) ) != 0 )
-        {
-            return( ret );
-        }
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
         return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
     }
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index ddedabb96..1e5f8e493 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3473,7 +3473,6 @@ static int ssl_handle_possible_reconnect( mbedtls_ssl_context *ssl )
  */
 static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
 {
-    int ret;
     int major_ver, minor_ver;
 
     MBEDTLS_SSL_DEBUG_BUF( 4, "input record header", ssl->in_hdr, mbedtls_ssl_hdr_len( ssl ) );
@@ -3494,14 +3493,8 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
         ssl->in_msgtype != MBEDTLS_SSL_MSG_APPLICATION_DATA )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "unknown record type" ) );
-
-        if( ( ret = mbedtls_ssl_send_alert_message( ssl,
-                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE ) ) != 0 )
-        {
-            return( ret );
-        }
-
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_INVALID_RECORD );
     }
 
@@ -4030,6 +4023,7 @@ int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl,
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> send alert message" ) );
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "send alert level=%u message=%u", level, message ));
 
     ssl->out_msgtype = MBEDTLS_SSL_MSG_ALERT;
     ssl->out_msglen = 2;
@@ -4041,7 +4035,6 @@ int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl,
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
         return( ret );
     }
-
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= send alert message" ) );
 
     return( 0 );
@@ -4057,6 +4050,7 @@ int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl,
     !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) && \
     !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)    && \
     !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+/* No certificate support -> dummy functions */
 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
@@ -4096,7 +4090,10 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
+
 #else
+/* Some certificate support -> implement write and parse */
+
 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
@@ -4219,6 +4216,7 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
     size_t i, n;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
     int authmode = ssl->conf->authmode;
+    uint8_t alert;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
 
@@ -4258,6 +4256,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
 
     if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
     {
+        /* mbedtls_ssl_read_record may have sent an alert already. We
+           let it decide whether to alert. */
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
     }
@@ -4279,6 +4279,9 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
 
+            /* The client was asked for a certificate but didn't send
+               one. The client should know what's going on, so we
+               don't send an alert. */
             ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
             if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
                 return( 0 );
@@ -4300,6 +4303,9 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
 
+            /* The client was asked for a certificate but didn't send
+               one. The client should know what's going on, so we
+               don't send an alert. */
             ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
             if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
                 return( 0 );
@@ -4314,6 +4320,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -4321,6 +4329,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 3 + 3 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
     }
 
@@ -4335,6 +4345,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         ssl->in_hslen != n + 3 + mbedtls_ssl_hs_hdr_len( ssl ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
     }
 
@@ -4350,6 +4362,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
                        sizeof( mbedtls_x509_crt ) ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
         return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
     }
 
@@ -4362,6 +4376,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         if( ssl->in_msg[i] != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
         }
 
@@ -4372,13 +4388,33 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         if( n < 128 || i + n > ssl->in_hslen )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
         }
 
         ret = mbedtls_x509_crt_parse_der( ssl->session_negotiate->peer_cert,
                                   ssl->in_msg + i, n );
-        if( 0 != ret && ( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND ) != ret )
+        switch( ret )
         {
+        case 0: /*ok*/
+        case MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND:
+            /* Ignore certificate with an unknown algorithm: maybe a
+               prior certificate was already trusted. */
+            break;
+
+        case MBEDTLS_ERR_X509_ALLOC_FAILED:
+            alert = MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR;
+            goto crt_parse_der_failed;
+
+        case MBEDTLS_ERR_X509_UNKNOWN_VERSION:
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            goto crt_parse_der_failed;
+
+        default:
+            alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
+        crt_parse_der_failed:
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, alert );
             MBEDTLS_SSL_DEBUG_RET( 1, " mbedtls_x509_crt_parse_der", ret );
             return( ret );
         }
@@ -4399,6 +4435,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         if( ssl->session->peer_cert == NULL )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "new server cert during renegotiation" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
         }
 
@@ -4409,6 +4447,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
                     ssl->session->peer_cert->raw.len ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "server cert changed during renegotiation" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
         }
     }
@@ -4435,6 +4475,8 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
         if( ca_chain == NULL )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_BAD_CERT );
             return( MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED );
         }
 
@@ -4485,6 +4527,37 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
 
         if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
             ret = 0;
+
+        if( ret != 0 )
+        {
+            /* The certificate may have been rejected for several reasons.
+               Pick one and send the corresponding alert. Which alert to send
+               may be a subject of debate in some cases. */
+            if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_OTHER )
+                alert = MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH )
+                alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_KEY_USAGE )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXT_KEY_USAGE )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NS_CERT_TYPE )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_PK )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_KEY )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXPIRED )
+                alert = MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_REVOKED )
+                alert = MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED;
+            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED )
+                alert = MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA;
+            else
+                alert = MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN;
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            alert );
+        }
     }
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );
@@ -4537,12 +4610,16 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
     if( ssl->in_msglen != 1 || ssl->in_msg[0] != 1 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC );
     }
 
@@ -4565,6 +4642,8 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
         if( ++ssl->in_epoch == 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS epoch would wrap" ) );
+            /* This is highly unlikely to happen for legitimate reasons, so
+               treat it as an attack and don't send an alert. */
             return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
         }
     }
@@ -4589,6 +4668,8 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
         if( ( ret = mbedtls_ssl_hw_record_activate( ssl, MBEDTLS_SSL_CHANNEL_INBOUND ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_activate", ret );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
         }
     }
@@ -5167,6 +5248,8 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
@@ -5182,6 +5265,8 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
         ssl->in_hslen  != mbedtls_ssl_hs_hdr_len( ssl ) + hash_len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_FINISHED );
     }
 
@@ -5189,6 +5274,8 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
                       buf, hash_len ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_FINISHED );
     }
 
@@ -6651,11 +6738,11 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
 #if defined(MBEDTLS_SSL_PROTO_SSL3)
                 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
                 {
-                    /*
-                     * SSLv3 does not have a "no_renegotiation" alert
-                     */
-                    if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
-                        return( ret );
+                    /* SSLv3 does not have a "no_renegotiation" warning, so
+                       we send a fatal alert and abort the connection. */
+                    mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                    MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
+                    return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
                 }
                 else
 #endif /* MBEDTLS_SSL_PROTO_SSL3 */
diff --git a/tests/scripts/run-test-suites.pl b/tests/scripts/run-test-suites.pl
index 58f827c14..1f73a545e 100755
--- a/tests/scripts/run-test-suites.pl
+++ b/tests/scripts/run-test-suites.pl
@@ -33,7 +33,10 @@ if ( defined($switch) && ( $switch eq "-v" || $switch eq "--verbose" ) ) {
     $verbose = TRUE;
 }
 
-my @suites = grep { ! /\.(?:c|gcno|gcda|dSYM)$/ } glob 'test_suite_*';
+# All test suites = executable files, excluding source files, debug
+# and profiling information, etc. We can't just grep {! /\./} because
+#some of our test cases' base names contain a dot.
+my @suites = grep { -x $_ || /\.exe$/ } glob 'test_suite_*';
 die "$0: no test suite found\n" unless @suites;
 
 # in case test suites are linked dynamically
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 61c382742..398405bdd 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -49,15 +49,23 @@ RUN_TEST_NUMBER=''
 
 PRESERVE_LOGS=0
 
+# Pick a "unique" server port in the range 10000-19999, and a proxy
+# port which is this plus 10000. Each port number may be independently
+# overridden by a command line option.
+SRV_PORT=$(($$ % 10000 + 10000))
+PXY_PORT=$((SRV_PORT + 10000))
+
 print_usage() {
     echo "Usage: $0 [options]"
     printf "  -h|--help\tPrint this help.\n"
     printf "  -m|--memcheck\tCheck memory leaks and errors.\n"
-    printf "  -f|--filter\tOnly matching tests are executed (default: '$FILTER')\n"
-    printf "  -e|--exclude\tMatching tests are excluded (default: '$EXCLUDE')\n"
+    printf "  -f|--filter\tOnly matching tests are executed (BRE; default: '$FILTER')\n"
+    printf "  -e|--exclude\tMatching tests are excluded (BRE; default: '$EXCLUDE')\n"
     printf "  -n|--number\tExecute only numbered test (comma-separated, e.g. '245,256')\n"
     printf "  -s|--show-numbers\tShow test numbers in front of test names\n"
     printf "  -p|--preserve-logs\tPreserve logs of successful tests as well\n"
+    printf "     --port\tTCP/UDP port (default: randomish 1xxxx)\n"
+    printf "     --proxy-port\tTCP/UDP proxy port (default: randomish 2xxxx)\n"
     printf "     --seed\tInteger seed value to use for this test run\n"
 }
 
@@ -82,6 +90,12 @@ get_options() {
             -p|--preserve-logs)
                 PRESERVE_LOGS=1
                 ;;
+            --port)
+                shift; SRV_PORT=$1
+                ;;
+            --proxy-port)
+                shift; PXY_PORT=$1
+                ;;
             --seed)
                 shift; SEED="$1"
                 ;;
@@ -611,13 +625,6 @@ fi
 CLI_DELAY_FACTOR=1
 SRV_DELAY_SECONDS=0
 
-# Pick a "unique" server port in the range 10000-19999, and a proxy port
-PORT_BASE="0000$$"
-PORT_BASE="$( printf $PORT_BASE | tail -c 4 )"
-SRV_PORT="1$PORT_BASE"
-PXY_PORT="2$PORT_BASE"
-unset PORT_BASE
-
 # fix commands to use this port, force IPv4 while at it
 # +SRV_PORT will be replaced by either $SRV_PORT or $PXY_PORT later
 P_SRV="$P_SRV server_addr=127.0.0.1 server_port=$SRV_PORT"
@@ -1825,6 +1832,38 @@ run_test    "Authentication: client SHA384, server required" \
             -c "Supported Signature Algorithm found: 4," \
             -c "Supported Signature Algorithm found: 5,"
 
+requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
+run_test    "Authentication: client has no cert, server required (SSLv3)" \
+            "$P_SRV debug_level=3 min_version=ssl3 auth_mode=required" \
+            "$P_CLI debug_level=3 force_version=ssl3 crt_file=none \
+             key_file=data_files/server5.key" \
+            1 \
+            -S "skip write certificate request" \
+            -C "skip parse certificate request" \
+            -c "got a certificate request" \
+            -c "got no certificate to send" \
+            -S "x509_verify_cert() returned" \
+            -s "client has no certificate" \
+            -s "! mbedtls_ssl_handshake returned" \
+            -c "! mbedtls_ssl_handshake returned" \
+            -s "No client certification received from the client, but required by the authentication mode"
+
+run_test    "Authentication: client has no cert, server required (TLS)" \
+            "$P_SRV debug_level=3 auth_mode=required" \
+            "$P_CLI debug_level=3 crt_file=none \
+             key_file=data_files/server5.key" \
+            1 \
+            -S "skip write certificate request" \
+            -C "skip parse certificate request" \
+            -c "got a certificate request" \
+            -c "= write certificate$" \
+            -C "skip write certificate$" \
+            -S "x509_verify_cert() returned" \
+            -s "client has no certificate" \
+            -s "! mbedtls_ssl_handshake returned" \
+            -c "! mbedtls_ssl_handshake returned" \
+            -s "No client certification received from the client, but required by the authentication mode"
+
 run_test    "Authentication: client badcert, server required" \
             "$P_SRV debug_level=3 auth_mode=required" \
             "$P_CLI debug_level=3 crt_file=data_files/server5-badsign.crt \
@@ -1839,8 +1878,12 @@ run_test    "Authentication: client badcert, server required" \
             -s "x509_verify_cert() returned" \
             -s "! The certificate is not correctly signed by the trusted CA" \
             -s "! mbedtls_ssl_handshake returned" \
+            -s "send alert level=2 message=48" \
             -c "! mbedtls_ssl_handshake returned" \
             -s "X509 - Certificate verification failed"
+# We don't check that the client receives the alert because it might
+# detect that its write end of the connection is closed and abort
+# before reading the alert message.
 
 run_test    "Authentication: client cert not trusted, server required" \
             "$P_SRV debug_level=3 auth_mode=required" \
@@ -1930,6 +1973,16 @@ run_test    "Authentication: client no cert, openssl server optional" \
             -c "skip write certificate verify" \
             -C "! mbedtls_ssl_handshake returned"
 
+run_test    "Authentication: client no cert, openssl server required" \
+            "$O_SRV -Verify 10" \
+            "$P_CLI debug_level=3 crt_file=none key_file=none" \
+            1 \
+            -C "skip parse certificate request" \
+            -c "got a certificate request" \
+            -C "skip write certificate$" \
+            -c "skip write certificate verify" \
+            -c "! mbedtls_ssl_handshake returned"
+
 requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
 run_test    "Authentication: client no cert, ssl3" \
             "$P_SRV debug_level=3 auth_mode=optional force_version=ssl3" \