diff --git a/cmd/ipbl/ipbl.go b/cmd/ipbl/ipbl.go
index 47f75e8..62e7df8 100644
--- a/cmd/ipbl/ipbl.go
+++ b/cmd/ipbl/ipbl.go
@@ -17,6 +17,7 @@ import (
 func main() {
 	var ctx context.Context
 	var cfg config.Config
+	var lock bool
 	cfg.GetConfig()
 	cfg.Options.Version = version
 
@@ -28,12 +29,12 @@ func main() {
 	defer cfg.Db.Close()
 
 	// Handles IP with no reverse DNS
-	go models.ScanIP(&cfg)
+	go models.ScanIP(&cfg, &lock)
 
 	// Add cron task to handle them
 	cr := cron.New()
 	cr.AddFunc("0 * * * * *", func() {
-		models.ScanIP(&cfg)
+		models.ScanIP(&cfg, &lock)
 	})
 	cr.Start()
 
diff --git a/src/models/ip.go b/src/models/ip.go
index 8c96463..2984df7 100644
--- a/src/models/ip.go
+++ b/src/models/ip.go
@@ -64,30 +64,33 @@ func InsertIPBulk(cfg *config.Config, ips *[]IP) (numinserts int64, numfail int6
 	return
 }
 
-func ScanIP(cfg *config.Config) (err error) {
-	for {
-		var orphans = []IP{}
-		cfg.Db.Where("rdns IS NULL").Asc("ip").Find(&orphans)
-		if len(orphans) > 0 {
-			for _, i := range orphans {
-				reverse, _ := i.UpdateRDNS()
-				if reverse == "" {
-					fmt.Printf("Set \"none\" rdns to IP %s\n", i.IP)
-					i.Rdns.String = "none"
-				} else {
-					fmt.Printf("%s %s\n", i.IP, reverse)
-					i.Rdns.String = reverse
-				}
-				i.Rdns.Valid = true
-				_, err = cfg.Db.ID(i.ID).Cols("rdns").Update(&i)
-				if err != nil {
-					log.Println(err)
+func ScanIP(cfg *config.Config, lock *bool) (err error) {
+	if !*lock {
+		for {
+			var orphans = []IP{}
+			cfg.Db.Where("rdns IS NULL").Asc("ip").Find(&orphans)
+			if len(orphans) > 0 {
+				for _, i := range orphans {
+					reverse, _ := i.UpdateRDNS()
+					if reverse == "" {
+						fmt.Printf("Set \"none\" rdns to IP %s\n", i.IP)
+						i.Rdns.String = "none"
+					} else {
+						fmt.Printf("%s %s\n", i.IP, reverse)
+						i.Rdns.String = reverse
+					}
+					i.Rdns.Valid = true
+					_, err = cfg.Db.ID(i.ID).Cols("rdns").Update(&i)
+					if err != nil {
+						log.Println(err)
+					}
 				}
+			} else {
+				break
 			}
-		} else {
-			break
 		}
 	}
+	*lock = false
 	return
 }