diff --git a/prometheus/main.go b/prometheus/main.go
index 520b1c9..2a887d8 100644
--- a/prometheus/main.go
+++ b/prometheus/main.go
@@ -169,11 +169,20 @@ func handleMetric(line string, metrics *metrics) {
 	fields := strings.Fields(line)
 	log.Println(fields)
 
+	if len(fields) < 2 {
+		log.Printf("Malformed metric line (need at least 2 fields): %q", line)
+		return
+	}
+
 	server := fields[0]
 	command := fields[1]
 
 	switch command {
 	case "connect":
+		if len(fields) < 3 {
+			log.Printf("Malformed connect metric (need 3 fields): %q", line)
+			return
+		}
 		ip := fields[2]
 		country := geoLookup(ip)
 		lat := CapitalCoordinates[country].Latitude
@@ -181,6 +190,10 @@ func handleMetric(line string, metrics *metrics) {
 		// Reduce cardinality by removing ip
 		handleConnect(server, country, lat, lon, metrics)
 	case "disconnect":
+		if len(fields) < 4 {
+			log.Printf("Malformed disconnect metric (need 4 fields): %q", line)
+			return
+		}
 		// ip := fields[2]
 		parsedTimeTrapped, err := strconv.ParseUint(fields[3], 10, 64)
 		if err != nil {
@@ -199,16 +212,28 @@ func handleMetric(line string, metrics *metrics) {
 		if len(fields) >= 4 {
 			url = fields[3]
 		}
-		
+
 		metrics.upnpOtherHttpRequests.WithLabelValues(method, url).Inc()
 	case "M-SEARCH":
+		if len(fields) < 3 {
+			log.Printf("Malformed M-SEARCH metric (need 3 fields): %q", line)
+			return
+		}
 		ip := fields[2]
 		metrics.upnpMSearchRequests.WithLabelValues(ip).Inc()
 	case "non-M-SEARCH":
+		if len(fields) < 3 {
+			log.Printf("Malformed non-M-SEARCH metric (need 3 fields): %q", line)
+			return
+		}
 		ip := fields[2]
 		metrics.upnpNonMSearchRequests.WithLabelValues(ip).Inc()
 	// MQTT
 	case "CONNECT":
+		if len(fields) < 3 {
+			log.Printf("Malformed MQTT CONNECT metric (need 3 fields): %q", line)
+			return
+		}
 		version := fields[2]
 		metrics.mqttConnectVersions.WithLabelValues(version).Inc()
 
@@ -216,6 +241,10 @@ func handleMetric(line string, metrics *metrics) {
 		metrics.mqttMalformedConnect.Inc()
 
 	case "SUBSCRIBE":
+		if len(fields) < 4 {
+			log.Printf("Malformed SUBSCRIBE metric (need 4 fields): %q", line)
+			return
+		}
 		topic := fields[2]
 		qos := fields[3]
 		metrics.mqttSubscribeTopics.WithLabelValues(topic, qos).Inc()
@@ -229,10 +258,14 @@ func handleMetric(line string, metrics *metrics) {
 		if len(fields) >= 4 {
 			password = fields[3]
 		}
-		
+
 		metrics.mqttCredentials.WithLabelValues(username, password).Inc()
 
 	case "PUBLISH":
+		if len(fields) < 4 {
+			log.Printf("Malformed PUBLISH metric (need 4 fields): %q", line)
+			return
+		}
 		topic := fields[2]
 		qos := fields[3]
 		metrics.mqttPublishTopics.WithLabelValues(topic, qos).Inc()