diff --git a/ospfd/ospf_main.c b/ospfd/ospf_main.c
index 27a12dd..1a200a8 100644
--- a/ospfd/ospf_main.c
+++ b/ospfd/ospf_main.c
@@ -245,7 +245,8 @@
               break;
             } 
           vty_port = atoi (optarg);
-          vty_port = (vty_port ? vty_port : OSPF_VTY_PORT);
+          if (vty_port <= 0 || vty_port > 0xffff)
+            vty_port = OSPF_VTY_PORT;
   	  break;
 	case 'u':
 	  ospfd_privs.user = optarg;