diff --git a/www/opendoor b/www/opendoor
index 9b89ef6..aa15dc8 100644
--- a/www/opendoor
+++ b/www/opendoor
@@ -1,4 +1,5 @@
 #!/bin/sh
+
 echo "* try to open tronlab's moleflap"
 
 HOST='moleflap.hq.c3d2.de'
@@ -10,6 +11,7 @@ PREFIX_LEN=4
 PORT=80
 STORE_ENC="$STORE.enc"
 STORE_TMP="$STORE.tmp"
+LOCKFILE="$STORE.lock"
 
 FORCE_PGP=0
 WGET="wget"
@@ -18,10 +20,15 @@ checkhost() {
 	# checks if host is reachable. returns 0 on success
 	ping6 -c 1 $HOST >/dev/null 2>/dev/null
 	if [ $? -eq 0 ]; then 
-        WGET="wget --prefer-family=IPv6"
-        return 0; 
-    fi
-	ping -c 1 $HOST >/dev/null 2>/dev/null
+    	    WGET="wget --prefer-family=IPv6"
+    	    return 0; 
+	fi
+	if [ "cygwin" = `uname -o | tr [:upper:] [:lower:]` ]
+	then
+	    ping $HOST 56 1 >/dev/null 2>/dev/null
+	else
+	    ping -c 1 $HOST >/dev/null 2>/dev/null
+	fi
 	if [ $? -eq 0 ]; then return 0; fi
 	return 1;
 }
@@ -107,6 +114,11 @@ EOF
 exit
 }
 
+removelock()
+{
+    rm $LOCKFILE
+}
+
 # Process command line arguments
 for i in $@; do
         case "$i" in
@@ -117,23 +129,33 @@ for i in $@; do
         esac
 done
 
+# lockfile
+if [ -e $LOCKFILE ]
+then
+    echo "lockfile exists ... exiting"
+    exit 1
+else
+    echo $(date) > $LOCKFILE
+fi
+
 # test for connection
 checkhost
 if [ "$?" -eq "1" ]
 then
 	if [ "x$CONNECT" = "x" ]; then
-		echo "can't connect to host $HOST"
-		exit;
+		echo "can't ping host $HOST ... exiting"
+		removelock
+		exit 1;
 	else
 		$CONNECT;
 	fi
 fi
 
-
 do_pgp
 if [ $? -gt 2 ]; then
-    echo "fatal error"
-    exit
+    echo "fatal error ... exiting"
+    removelock
+    exit 1
 fi 
 
 if [ -e $STORE ]
@@ -143,7 +165,7 @@ else
 	echo "Please enter your valid token:"
 	read token
 	# save new token first
-    echo "$token" > $STORE
+	echo "$token" > $STORE
 fi
 
 newtoken=`$WGET -qO - http://$HOST:$PORT/open?$token`
@@ -156,3 +178,4 @@ else
 	echo "* moleflap unreachable"
 fi
 
+removelock