diff --git a/src/esp8266/sdk_lwip/include/lwip/def.h b/src/esp8266/sdk_lwip/include/lwip/def.h
index 9b6de6a..2bbfcac 100644
--- a/src/esp8266/sdk_lwip/include/lwip/def.h
+++ b/src/esp8266/sdk_lwip/include/lwip/def.h
@@ -43,6 +43,9 @@ extern "C" {
 #define LWIP_MAX(x , y)  (((x) > (y)) ? (x) : (y))
 #define LWIP_MIN(x , y)  (((x) < (y)) ? (x) : (y))
 
+/* Get the number of entries in an array ('x' must NOT be a pointer!) */
+#define LWIP_ARRAYSIZE(x) (sizeof(x)/sizeof((x)[0]))
+
 #ifndef NULL
 #define NULL ((void *)0)
 #endif
diff --git a/src/esp8266/sdk_lwip/include/lwip/dhcp.h b/src/esp8266/sdk_lwip/include/lwip/dhcp.h
index 57baab3..f4a6ae4 100644
--- a/src/esp8266/sdk_lwip/include/lwip/dhcp.h
+++ b/src/esp8266/sdk_lwip/include/lwip/dhcp.h
@@ -205,12 +205,13 @@ void dhcp_fine_tmr(void);
 #define DHCP_OPTION_PAD 0
 #define DHCP_OPTION_SUBNET_MASK 1 /* RFC 2132 3.3 */
 #define DHCP_OPTION_ROUTER 3
-#define DHCP_OPTION_DNS_SERVER 6 
+#define DHCP_OPTION_DNS_SERVER 6
 #define DHCP_OPTION_HOSTNAME 12
 #define DHCP_OPTION_IP_TTL 23
 #define DHCP_OPTION_MTU 26
 #define DHCP_OPTION_BROADCAST 28
 #define DHCP_OPTION_TCP_TTL 37
+#define DHCP_OPTION_NTP 42
 #define DHCP_OPTION_END 255
 
 /**add options for support more router by liuHan**/
diff --git a/src/esp8266/sdk_lwip/src/core/dhcp.c b/src/esp8266/sdk_lwip/src/core/dhcp.c
index 91c3393..1df0e3f 100755
--- a/src/esp8266/sdk_lwip/src/core/dhcp.c
+++ b/src/esp8266/sdk_lwip/src/core/dhcp.c
@@ -132,6 +132,14 @@ u32_t dhcp_rx_options_val[DHCP_OPTION_IDX_MAX];
     @todo: move this into struct dhcp? */
 u8_t  dhcp_rx_options_given[DHCP_OPTION_IDX_MAX];
 
+static const u8_t dhcp_discover_request_options[] = {
+  DHCP_OPTION_SUBNET_MASK,
+  DHCP_OPTION_ROUTER,
+  DHCP_OPTION_BROADCAST,
+  DHCP_OPTION_DNS_SERVER,
+  DHCP_OPTION_NTP,
+};
+
 #define dhcp_option_given(dhcp, idx)          (dhcp_rx_options_given[idx] != 0)
 #define dhcp_got_option(dhcp, idx)            (dhcp_rx_options_given[idx] = 1)
 #define dhcp_clear_option(dhcp, idx)          (dhcp_rx_options_given[idx] = 0)
@@ -314,19 +322,10 @@ dhcp_select(struct netif *netif)
     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->server_ip_addr)));
 
-    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 12/*num options*/);
-    dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
-    dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
-    dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
-    dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
-    dhcp_option_byte(dhcp, DHCP_OPTION_DOMAIN_NAME);
-        dhcp_option_byte(dhcp, DHCP_OPTION_NB_TINS);
-        dhcp_option_byte(dhcp, DHCP_OPTION_NB_TINT);
-        dhcp_option_byte(dhcp, DHCP_OPTION_NB_TIS);
-        dhcp_option_byte(dhcp, DHCP_OPTION_PRD);
-        dhcp_option_byte(dhcp, DHCP_OPTION_STATIC_ROUTER);
-        dhcp_option_byte(dhcp, DHCP_OPTION_CLASSLESS_STATIC_ROUTER);
-        dhcp_option_byte(dhcp, DHCP_OPTION_VSN);
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, LWIP_ARRAYSIZE(dhcp_discover_request_options));
+    for (u8_t i = 0; i < LWIP_ARRAYSIZE(dhcp_discover_request_options); i++) {
+      dhcp_option_byte(dhcp, dhcp_discover_request_options[i]);
+    }
 
 #if LWIP_NETIF_HOSTNAME
     if (netif->hostname != NULL) {
@@ -963,19 +962,10 @@ dhcp_discover(struct netif *netif)
       }
     }
 
-    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 12/*num options*/);
-    dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
-    dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
-    dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
-    dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
-    dhcp_option_byte(dhcp, DHCP_OPTION_DOMAIN_NAME);
-            dhcp_option_byte(dhcp, DHCP_OPTION_NB_TINS);
-            dhcp_option_byte(dhcp, DHCP_OPTION_NB_TINT);
-            dhcp_option_byte(dhcp, DHCP_OPTION_NB_TIS);
-            dhcp_option_byte(dhcp, DHCP_OPTION_PRD);
-            dhcp_option_byte(dhcp, DHCP_OPTION_STATIC_ROUTER);
-            dhcp_option_byte(dhcp, DHCP_OPTION_CLASSLESS_STATIC_ROUTER);
-            dhcp_option_byte(dhcp, DHCP_OPTION_VSN);
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, LWIP_ARRAYSIZE(dhcp_discover_request_options));
+    for (u8_t i = 0; i < LWIP_ARRAYSIZE(dhcp_discover_request_options); i++) {
+      dhcp_option_byte(dhcp, dhcp_discover_request_options[i]);
+    }
 
     dhcp_option_trailer(dhcp);
 
@@ -1148,6 +1138,11 @@ dhcp_renew(struct netif *netif)
     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
 
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, LWIP_ARRAYSIZE(dhcp_discover_request_options));
+    for (u8_t i = 0; i < LWIP_ARRAYSIZE(dhcp_discover_request_options); i++) {
+      dhcp_option_byte(dhcp, dhcp_discover_request_options[i]);
+    }
+
 #if LWIP_NETIF_HOSTNAME
     if (netif->hostname != NULL) {
       const char *p = (const char*)netif->hostname;
@@ -1223,6 +1218,11 @@ dhcp_rebind(struct netif *netif)
     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
 
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, LWIP_ARRAYSIZE(dhcp_discover_request_options));
+    for (u8_t i = 0; i < LWIP_ARRAYSIZE(dhcp_discover_request_options); i++) {
+      dhcp_option_byte(dhcp, dhcp_discover_request_options[i]);
+    }
+
 #if LWIP_NETIF_HOSTNAME
     if (netif->hostname != NULL) {
       const char *p = (const char*)netif->hostname;
@@ -1298,6 +1298,11 @@ dhcp_reboot(struct netif *netif)
     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
 
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, LWIP_ARRAYSIZE(dhcp_discover_request_options));
+    for (u8_t i = 0; i < LWIP_ARRAYSIZE(dhcp_discover_request_options); i++) {
+      dhcp_option_byte(dhcp, dhcp_discover_request_options[i]);
+    }
+
     dhcp_option_trailer(dhcp);
 
     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);