diff --git a/cmd/agent/service.go b/cmd/agent/service.go
index 2ec18e6..c1532c8 100644
--- a/cmd/agent/service.go
+++ b/cmd/agent/service.go
@@ -333,7 +333,7 @@ func natPMP(config *conf.C) {
 		return
 	}
 
-	portMapping, err := client.AddPortMapping("udp", nebulaPort, 0, 120)
+	portMapping, err := client.AddPortMapping("udp", nebulaPort, 0, int(config.GetDuration("service.port_mapping.lifetime", 24*time.Hour).Seconds()))
 	if err != nil {
 		fmt.Printf("%s\n", err)
 		return
diff --git a/examples/agent.yml b/examples/agent.yml
index 9cc2337..ecce891 100644
--- a/examples/agent.yml
+++ b/examples/agent.yml
@@ -15,6 +15,7 @@ service:
 #  port_mapping:
 #    enabled: true
 #    gateway: 192.168.56.101
+#    lifetime: 24h
 
 #enroll:
 #  groups: ["test"]