diff --git a/w4it-for-port-open/w4it-for-port-open b/w4it-for-port-open/w4it-for-port-open
index 7517934..cc21210 100755
--- a/w4it-for-port-open/w4it-for-port-open
+++ b/w4it-for-port-open/w4it-for-port-open
@@ -3,6 +3,8 @@
 HOST=$1
 PORT=$2
 
+TCPTRACEROUTE=$( which tcptraceroute )
+
 usage () {
   echo "Usage:"
   echo "  $0 host [port]"
@@ -28,7 +30,6 @@ print_up_but_port_closed () {
   fi
 }
 
-
 port_is_open () {
     # If tcptraceroute stops working use:
     # echo | nc -w 2 $HOST $PORT || failed
@@ -51,6 +52,10 @@ fi
 if [ -z "$PORT" ] ; then
   PORT=22
 fi
+if [ -z "$TCPTRACEROUTE" ] ; then
+  echo "Error, 'tcptraceroute' not installed."
+  exit 2
+fi
 
 port_is_open
 while [ "$OPEN" = "no" ] ; do