diff --git a/config.default.yml b/config.default.yml
index de6be51..374ed4a 100644
--- a/config.default.yml
+++ b/config.default.yml
@@ -1,4 +1,6 @@
-url: ''
+url:
+  v4: ''
+  v6: ''
 verify_value: ''
 domains:
   - name: ''
diff --git a/module/config/config.go b/module/config/config.go
index cc74588..a6d8887 100644
--- a/module/config/config.go
+++ b/module/config/config.go
@@ -12,19 +12,22 @@ import (
 
 // RecordData -
 type RecordData struct {
-	Name string `yaml:"name"`
-	Type string `yaml:"type"`
+	Name string `yaml:"name" json:"name"`
+	Type string `yaml:"type" json:"type"`
 }
 
 // DomainData -
 type DomainData struct {
-	Name    string       `yaml:"name"`
-	Records []RecordData `yaml:"records"`
+	Name    string       `yaml:"name" json:"name"`
+	Records []RecordData `yaml:"records" json:"records"`
 }
 
 // Config -
 type Config struct {
-	URL         string       `yaml:"url"`
+	URL struct {
+		V4 string `yaml:"v4"`
+		V6 string `yaml:"v6"`
+	} `yaml:"url"`
 	VerifyValue string       `yaml:"verify_value"`
 	Domains     []DomainData `yaml:"domains"`
 }
@@ -66,3 +69,6 @@ func LoadConfig(p ...string) error {
 
 // GetConfig -
 func GetConfig() *Config { return conf }
+
+// GetV4Data -
+func (p DomainData) GetV4Data() {}
diff --git a/module/ddns/ddns.go b/module/ddns/ddns.go
new file mode 100644
index 0000000..a958bb9
--- /dev/null
+++ b/module/ddns/ddns.go
@@ -0,0 +1,25 @@
+package ddns
+
+import (
+	"errors"
+
+	"git.trj.tw/golang/go-ddns-client/module/config"
+)
+
+// Errors
+var (
+	ErrNoDomain = errors.New("No Domain Setting")
+)
+
+// SendDNSSetting -
+func SendDNSSetting() error {
+	conf := config.GetConfig()
+	if len(conf.Domains) == 0 {
+		return ErrNoDomain
+	}
+	return nil
+}
+
+func parseConf(domains []config.DomainData) {
+
+}
diff --git a/module/option/option.go b/module/option/option.go
index 022246c..e35b4dc 100644
--- a/module/option/option.go
+++ b/module/option/option.go
@@ -6,6 +6,7 @@ import "flag"
 type Options struct {
 	Help   bool
 	Config string
+	Once   bool
 }
 
 var opts *Options
@@ -16,6 +17,7 @@ func RegOptions() {
 	flag.StringVar(&opts.Config, "config", "", "config file path - default: `pwd/config.yml`")
 	flag.StringVar(&opts.Config, "f", "", "config file path - default: `pwd/config.yml`")
 	flag.BoolVar(&opts.Help, "help", false, "show help")
+	flag.BoolVar(&opts.Once, "once", false, "run once")
 	flag.Parse()
 }