diff --git a/config_sample.json b/config_sample.json
index 7eb6785..4288d06 100644
--- a/config_sample.json
+++ b/config_sample.json
@@ -19,6 +19,7 @@
     }
   ],
   "ip_url": "http://members.3322.org/dyndns/getip",
+  "ip_interface": "eth0",
   "socks5_proxy": "",
   "notify": {
     "enabled": false,
diff --git a/handler/cloudflare_handler.go b/handler/cloudflare_handler.go
index ba0346f..1ee4da3 100644
--- a/handler/cloudflare_handler.go
+++ b/handler/cloudflare_handler.go
@@ -74,6 +74,7 @@ func (handler *CloudflareHandler) DomainLoop(domain *godns.Domain, panicChan cha
 		}
 	}()
 
+	var lastIP string
 	for {
 		currentIP, err := godns.GetCurrentIP(handler.Configuration)
 		if err != nil {
@@ -81,30 +82,34 @@ func (handler *CloudflareHandler) DomainLoop(domain *godns.Domain, panicChan cha
 			continue
 		}
 		log.Println("Current IP is:", currentIP)
-		// TODO: check against locally cached IP, if no change, skip update
-
-		log.Println("Checking IP for domain", domain.DomainName)
-		zoneID := handler.getZone(domain.DomainName)
-		if zoneID != "" {
-			records := handler.getDNSRecords(zoneID)
-
-			// update records
-			for _, rec := range records {
-				if recordTracked(domain, &rec) != true {
-					log.Println("Skiping record:", rec.Name)
-					continue
-				}
-				if rec.IP != currentIP {
-					log.Printf("IP mismatch: Current(%+v) vs Cloudflare(%+v)\r\n", currentIP, rec.IP)
-					handler.updateRecord(rec, currentIP)
-				} else {
-					log.Printf("Record OK: %+v - %+v\r\n", rec.Name, rec.IP)
-				}
-			}
+		//check against locally cached IP, if no change, skip update
+		if (currentIP == lastIP){
+			log.Printf("IP is the same as cached one. Skip update.\n")
 		} else {
-			log.Println("Failed to find zone for domain:", domain.DomainName)
-		}
+			lastIP = currentIP
 
+			log.Println("Checking IP for domain", domain.DomainName)
+			zoneID := handler.getZone(domain.DomainName)
+			if zoneID != "" {
+				records := handler.getDNSRecords(zoneID)
+
+				// update records
+				for _, rec := range records {
+					if recordTracked(domain, &rec) != true {
+						log.Println("Skiping record:", rec.Name)
+						continue
+					}
+					if rec.IP != currentIP {
+						log.Printf("IP mismatch: Current(%+v) vs Cloudflare(%+v)\r\n", currentIP, rec.IP)
+						handler.updateRecord(rec, currentIP)
+					} else {
+						log.Printf("Record OK: %+v - %+v\r\n", rec.Name, rec.IP)
+					}
+				}
+			} else {
+				log.Println("Failed to find zone for domain:", domain.DomainName)
+			}
+		}
 		// Interval is 5 minutes
 		log.Printf("Going to sleep, will start next checking in %d minutes...\r\n", godns.INTERVAL)
 		time.Sleep(time.Minute * godns.INTERVAL)
diff --git a/handler/dnspod_handler.go b/handler/dnspod_handler.go
index 590a277..ea116da 100644
--- a/handler/dnspod_handler.go
+++ b/handler/dnspod_handler.go
@@ -36,6 +36,7 @@ func (handler *DNSPodHandler) DomainLoop(domain *godns.Domain, panicChan chan<-
 		}
 	}()
 
+	var lastIP string
 	for {
 		log.Printf("Checking IP for domain %s \r\n", domain.DomainName)
 		domainID := handler.GetDomain(domain.DomainName)
@@ -52,31 +53,37 @@ func (handler *DNSPodHandler) DomainLoop(domain *godns.Domain, panicChan chan<-
 		}
 		log.Println("currentIP is:", currentIP)
 
-		for _, subDomain := range domain.SubDomains {
+		//check against locally cached IP, if no change, skip update
+		if (currentIP == lastIP){
+			log.Printf("IP is the same as cached one. Skip update.\n")
+		}else{
+			lastIP = currentIP
+			
+			for _, subDomain := range domain.SubDomains {
 
-			subDomainID, ip := handler.GetSubDomain(domainID, subDomain)
+				subDomainID, ip := handler.GetSubDomain(domainID, subDomain)
 
-			if subDomainID == "" || ip == "" {
-				log.Printf("domain: %s.%s subDomainID: %s ip: %s\n", subDomain, domain.DomainName, subDomainID, ip)
-				continue
-			}
-
-			// Continue to check the IP of sub-domain
-			if len(ip) > 0 && strings.TrimRight(currentIP, "\n") != strings.TrimRight(ip, "\n") {
-				log.Printf("%s.%s Start to update record IP...\n", subDomain, domain.DomainName)
-				handler.UpdateIP(domainID, subDomainID, subDomain, currentIP)
-
-				// Send mail notification if notify is enabled
-				if handler.Configuration.Notify.Enabled {
-					log.Print("Sending notification to:", handler.Configuration.Notify.SendTo)
-					godns.SendNotify(handler.Configuration, fmt.Sprintf("%s.%s", subDomain, domain.DomainName), currentIP)
+				if subDomainID == "" || ip == "" {
+					log.Printf("domain: %s.%s subDomainID: %s ip: %s\n", subDomain, domain.DomainName, subDomainID, ip)
+					continue
 				}
 
-			} else {
-				log.Printf("%s.%s Current IP is same as domain IP, no need to update...\n", subDomain, domain.DomainName)
-			}
-		}
+				// Continue to check the IP of sub-domain
+				if len(ip) > 0 && strings.TrimRight(currentIP, "\n") != strings.TrimRight(ip, "\n") {
+					log.Printf("%s.%s Start to update record IP...\n", subDomain, domain.DomainName)
+					handler.UpdateIP(domainID, subDomainID, subDomain, currentIP)
 
+					// Send mail notification if notify is enabled
+					if handler.Configuration.Notify.Enabled {
+						log.Print("Sending notification to:", handler.Configuration.Notify.SendTo)
+						godns.SendNotify(handler.Configuration, fmt.Sprintf("%s.%s", subDomain, domain.DomainName), currentIP)
+					}
+
+				} else {
+					log.Printf("%s.%s Current IP is same as domain IP, no need to update...\n", subDomain, domain.DomainName)
+				}
+			}
+		} 
 		// Interval is 5 minutes
 		log.Printf("Going to sleep, will start next checking in %d minutes...\r\n", godns.INTERVAL)
 		time.Sleep(time.Minute * godns.INTERVAL)
diff --git a/handler/he_handler.go b/handler/he_handler.go
index c34e02c..56dc92a 100644
--- a/handler/he_handler.go
+++ b/handler/he_handler.go
@@ -39,6 +39,7 @@ func (handler *HEHandler) DomainLoop(domain *godns.Domain, panicChan chan<- godn
 		}
 	}()
 
+	var lastIP string
 	for {
 		currentIP, err := godns.GetCurrentIP(handler.Configuration)
 
@@ -48,21 +49,28 @@ func (handler *HEHandler) DomainLoop(domain *godns.Domain, panicChan chan<- godn
 		}
 		log.Println("currentIP is:", currentIP)
 
-		for _, subDomain := range domain.SubDomains {
-			log.Printf("%s.%s Start to update record IP...\n", subDomain, domain.DomainName)
-			handler.UpdateIP(domain.DomainName, subDomain, currentIP)
+		//check against locally cached IP, if no change, skip update
+		if (currentIP == lastIP){
+			log.Printf("IP is the same as cached one. Skip update.\n")
+		} else {
+			lastIP = currentIP
+			
+			for _, subDomain := range domain.SubDomains {
+				log.Printf("%s.%s Start to update record IP...\n", subDomain, domain.DomainName)
+				handler.UpdateIP(domain.DomainName, subDomain, currentIP)
 
-			// Send mail notification if notify is enabled
-			if handler.Configuration.Notify.Enabled {
-				log.Print("Sending notification to:", handler.Configuration.Notify.SendTo)
-				godns.SendNotify(handler.Configuration, fmt.Sprintf("%s.%s", subDomain, domain.DomainName), currentIP)
+				// Send mail notification if notify is enabled
+				if handler.Configuration.Notify.Enabled {
+					log.Print("Sending notification to:", handler.Configuration.Notify.SendTo)
+					godns.SendNotify(handler.Configuration, fmt.Sprintf("%s.%s", subDomain, domain.DomainName), currentIP)
+				}
 			}
 		}
-
 		// Interval is 5 minutes
 		log.Printf("Going to sleep, will start next checking in %d minutes...\r\n", godns.INTERVAL)
 		time.Sleep(time.Minute * godns.INTERVAL)
 	}
+
 }
 
 // UpdateIP update subdomain with current IP
diff --git a/settings.go b/settings.go
index c287628..897e91b 100644
--- a/settings.go
+++ b/settings.go
@@ -33,6 +33,9 @@ type Settings struct {
 	LogPath     string   `json:"log_path"`
 	Socks5Proxy string   `json:"socks5_proxy"`
 	Notify      Notify   `json:"notify"`
+	IPInterface string   `json:"ip_interface"`
+	//the code is not ready to update AAAA record
+	//IPType      string   `json:"ip_type"`
 }
 
 // LoadSettings -- Load settings from config file
diff --git a/utils.go b/utils.go
index af69132..f2c1808 100644
--- a/utils.go
+++ b/utils.go
@@ -8,6 +8,7 @@ import (
 	"log"
 	"net/http"
 	"strings"
+    "net"
 
 	"golang.org/x/net/proxy"
 	"gopkg.in/gomail.v2"
@@ -43,8 +44,87 @@ const (
 	CLOUDFLARE = "Cloudflare"
 )
 
-// GetCurrentIP gets public IP from internet
+//GetIPFromInterface gets IP address from the specific interface
+func GetIPFromInterface(configuration *Settings) (string,error) {
+ 	ifaces, err := net.InterfaceByName(configuration.IPInterface)
+	if err != nil {
+		log.Println("can't get network device "+configuration.IPInterface+":", err)
+		return "", err
+	}
+
+	addrs, err  :=ifaces.Addrs();
+	if err != nil {
+		log.Println("can't get address from "+configuration.IPInterface+":", err)
+		return "", err
+	}
+
+	for _, addr := range addrs {
+		var ip net.IP
+		switch v := addr.(type) {
+		case *net.IPNet:
+			ip = v.IP
+		case *net.IPAddr:
+			ip = v.IP
+		}
+		if (ip == nil){
+			continue;
+		}
+
+		if (!(ip.IsGlobalUnicast() &&!(ip.IsUnspecified()||ip.IsMulticast()||ip.IsLoopback()||ip.IsLinkLocalUnicast()||ip.IsLinkLocalMulticast()||ip.IsInterfaceLocalMulticast()))){
+			continue;
+		} 
+
+		//the code is not ready for updating an AAAA record
+		/*
+		if (isIPv4(ip.String())){
+			if (configuration.IPType=="IPv6"){
+				continue;
+			}
+		}else{
+			if (configuration.IPType!="IPv6"){
+				continue;
+			}
+		} */
+		if (!isIPv4(ip.String())){
+			continue;
+		}
+
+		return ip.String(),nil
+		 
+	}
+	return "", errors.New("can't get a vaild address from "+configuration.IPInterface)
+}
+
+func isIPv4(ip string) bool{
+	return strings.Count(ip, ":") < 2
+}
+
+//GetCurrentIP gets an IP from either internet or specific interface, depending on configuration
 func GetCurrentIP(configuration *Settings) (string, error) {
+	var err error
+
+	if (configuration.IPUrl != ""){ 
+		ip, err := GetIPOnline(configuration)
+		if (err != nil){
+			log.Println("get ip online failed. Fallback to get ip from interface if possible.")
+		}else{
+			return ip,nil
+		}
+	}
+
+	if (configuration.IPInterface != ""){
+		ip, err := GetIPFromInterface(configuration)
+		if (err != nil){ 
+			log.Println("get ip from interface failed. There is no more ways to try.")
+		}else{
+			return ip,nil
+		}
+	}
+
+	return "", err
+}
+// GetIPOnline gets public IP from internet
+func GetIPOnline(configuration *Settings) (string, error) {
 	client := &http.Client{}
 
 	if configuration.Socks5Proxy != "" {