diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 66657da55..4956d0476 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1134,6 +1134,20 @@
  */
 #define MBEDTLS_SSL_DTLS_HELLO_VERIFY
 
+/**
+ * \def MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE
+ *
+ * Enable server-side support for clients that reconnect from the same port.
+ *
+ * Some clients unexpectedly close the connection and try to reconnect using the
+ * same source port. This needs special support from the server to handle the
+ * new connection securely, as described in section 4.1.8 of RFC 6347. This
+ * flag enables that support.
+ *
+ * Comment this to disable support for clients reusing the source port.
+ */
+#define MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE
+
 /**
  * \def MBEDTLS_SSL_DTLS_BADMAC_LIMIT
  *