diff --git a/genRevShell.py b/genRevShell.py
index 44c8219..453c345 100755
--- a/genRevShell.py
+++ b/genRevShell.py
@@ -5,6 +5,7 @@ import sys
 import pty
 import util
 import time
+import random
 import threading
 import readline
 import base64
@@ -137,11 +138,9 @@ if __name__ == "__main__":
 
     # choose random port
     if listen_port is None:
-        sock = util.openServer(local_address)
-        if not sock:
-            exit(1)
-        listen_port = sock.getsockname()[1]
-        sock.close()
+        listen_port = random.randint(10000,65535)
+        while util.isPortInUse(listen_port):
+            listen_port = random.randint(10000,65535)
 
     payload = generatePayload(payload_type, local_address, listen_port)
 
diff --git a/util.py b/util.py
index 78e2fe6..7ad255c 100755
--- a/util.py
+++ b/util.py
@@ -11,6 +11,12 @@ import io
 from PIL import Image
 from bs4 import BeautifulSoup
 
+def isPortInUse(port):
+    import socket
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+        return s.connect_ex(('127.0.0.1', port)) == 0
+
+
 def getAddress(interface="tun0"):
     if not interface in ni.interfaces():
         interfaces = ni.interfaces()