diff --git a/constant/metadata.go b/constant/metadata.go
index 3b55a8be..f1c68f68 100644
--- a/constant/metadata.go
+++ b/constant/metadata.go
@@ -135,7 +135,7 @@ type Metadata struct {
 	SpecialRules string     `json:"specialRules"`
 	RemoteDst    string     `json:"remoteDestination"`
 	// Only domain rule
-	SniffHost string
+	SniffHost string `json:"sniffHost"`
 }
 
 func (m *Metadata) RemoteAddress() string {