diff --git a/keydb_extension.go b/keydb_extension.go
index 63463f2..c4afcb2 100644
--- a/keydb_extension.go
+++ b/keydb_extension.go
@@ -20,7 +20,7 @@ func init() {
 type KeyDBHandler struct {
 	Address  string `json:"address"`
 	Password string `json:"password"`
-	DB       int    `json:"db"`
+	DB       string `json:"db"`
 	client   *redis.Client
 }
 
@@ -32,10 +32,17 @@ func (KeyDBHandler) CaddyModule() caddy.ModuleInfo {
 }
 
 func (h *KeyDBHandler) Provision(ctx caddy.Context) error {
+	db, err := strconv.Atoi(h.DB)
+	if err != nil {
+		return err
+	}
+	if db < 0 || db > 15 {
+		return fmt.Errorf("invalid db value: %d", db)
+	}
 	h.client = redis.NewClient(&redis.Options{
 		Addr:     h.Address,
 		Password: h.Password,
-		DB:       h.DB,
+		DB:       db,
 	})
 	return nil
 }
@@ -76,7 +83,7 @@ func (h *KeyDBHandler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 					return d.ArgErr()
 				}
 			case "db":
-				if !d.Args(strconv.Itoa(h.DB)) {
+				if !d.Args(&h.DB) {
 					return d.ArgErr()
 				}
 			}