+ /* Avoid temporary address, they are bad for long-lived
+ * connections such as NFS mounts.
+ * RFC4941, section 3.6 suggests that:
+ * Individual applications, which have specific
+ * knowledge about the normal duration of connections,
+ * MAY override this as appropriate.
+ */
+ kernel_setsockopt(sock, SOL_IPV6, IPV6_ADDR_PREFERENCES,
+ (char *)&addr_pref, sizeof(addr_pref));
+