diff --git a/install/usr/share/swarmlab.io/sec/swarmlab-sec b/install/usr/share/swarmlab.io/sec/swarmlab-sec
index 0f54800..873aa88 100755
--- a/install/usr/share/swarmlab.io/sec/swarmlab-sec
+++ b/install/usr/share/swarmlab.io/sec/swarmlab-sec
@@ -26,6 +26,20 @@
 
 set -e
 
+
+function EPHEMERAL_PORT() {
+    LOW_BOUND=49152
+    RANGE=16384
+    while true; do
+        CANDIDATE=$[$LOW_BOUND + ($RANDOM % $RANGE)]
+        (echo "" >/dev/tcp/127.0.0.1/${CANDIDATE}) >/dev/null 2>&1
+        if [ $? -ne 0 ]; then
+            echo $CANDIDATE
+            break
+        fi
+    done
+}
+
 DOCKERuser="docker"
 PACKAGES=$(cat <<EOF
 	net-tools  \