diff --git a/client/shell/yadync.sh b/client/shell/yadync.sh
index 8fdae78..665fa47 100755
--- a/client/shell/yadync.sh
+++ b/client/shell/yadync.sh
@@ -3,7 +3,7 @@
 SHAREDSECRET="test123"
 DYNID="testhost"
 DATE=`date +%s`
-CHECKSUM=`echo "$DYNID $SHAREDSECRET $DATE" | md5sum | awk '{print $1}'`
+CHECKSUM=`echo -n "$DYNID $SHAREDSECRET $DATE" | md5sum | awk '{print $1}'`
 OUT="$DYNID $DATE $CHECKSUM"
-echo $OUT | nc -q 0 -u 88.198.170.2 9090
+echo -n $OUT | nc -q 0 -u 127.0.0.1 9090
 
diff --git a/server/yadyn b/server/yadyn
old mode 100644
new mode 100755
index 1bc4a83..dccea0e
--- a/server/yadyn
+++ b/server/yadyn
@@ -1,111 +1,130 @@
 #!/usr/bin/python
 
-import select
 import socket
+import Queue
+import threading
+import md5
 import time
-import random
+
+class Entry(object):
+    def __init__(self, dynid, sharedSecret, name):
+        self.dynid = dynid
+        self.sharedSecret = sharedSecret
+        self.name = name
+        self.lastEventTime = 0
+        self.address = ''
+
+class IllegalEventException(Exception):
+    def __init__(self, msg):
+        self.msg = msg
 
 
-ALPHANUM = (0,1,2,3,4,5,6,7,8,9,
-            'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z')
-
-class DoneException(Exception): pass
-
-class TimeoutException(Exception): pass
-
-class Client(object):
-    def __init__(self, sock, address):
-        self.sock = sock
+class Event(object):
+    def __init__(self, address, data, receiveTime):
         self.address = address
-        self.timestamp = int(time.time())
-        self.timeout = 5
-        self.state = 0
+        self.data = data
+        self.receiveTime = receiveTime
+
+    def prepare(self):
+        self.port = self.address[1]
+        self.address = self.address[0]
+        (self.dynid, self.msgTime, self.checksum) = self.data.split(' ')
+        self.msgTime = int(self.msgTime)
+        self.prepared = True
 
     def process(self):
-        self.timestamp = int(time.time())
-        data = self.sock.recv(8192)
-        if data == None or data == '':
-            raise DoneException
-        if data[-1] in ('\r','\n'):
-            data = data[:-1]
-        if data[-1] in ('\r','\n'):
-            data = data[:-1]
-        print "<%s> %d" % (data, len(data))
+        if not self.prepared:
+            self.prepare()
+
+        if not ENTRIES.has_key(self.dynid):
+            raise IllegalEventException("unknown dynid in event %s" % str(self))
+        entry = ENTRIES[self.dynid]
+
+        if self.msgTime + MSG_TIME_CORRIDOR < self.receiveTime:
+            raise IllegalEventException("event too old %s" % str(self))
+        if self.msgTime - MSG_TIME_CORRIDOR > self.receiveTime:
+            raise IllegalEventException("event too young %s" % str(self))
 
 
-        if self.state == 0:
-            #print "State 0"
-            if data == "hello":
-                self.challenge = ''.join(random.sample(ALPHANUM, 5))
-                print self.challenge
-                self.sock.send(self.challenge)
-                self.state = 1
-                return
-            else:
-                raise DoneException
-        elif self.state == 1:
-            print "State 1"
-            if data == self.challenge:
-                self.sock.send("OK")
-            raise DoneException
+        if entry.lastEventTime >= self.msgTime:
+            raise IllegalEventException("timing sequence failure in event, possibly replay %s" % str(self))
 
-        print "After state machine"
+        di = "%s %s %d" % (self.dynid, entry.sharedSecret, self.msgTime)
+        d = md5.new(di).hexdigest()
+        print "%s, received: %s, calculated: %s" % (di, self.checksum, d)
+        if d != self.checksum:
+            raise IllegalEventException("wrong checksum for event %s" % str(self))
+
+        entry.lastEventTime = self.msgTime
+
+        if entry.address == self.address:
+            print "Same address, nothing to do."
+        else:
+            entry.address = self.address
+            print "Set in DNS: %s -> %s" % (entry.name, entry.address)
 
 
+    def __str__(self):
+        if not self.prepared:
+            self.prepare()
+        return "%s from %s:%d" % (self.data, self.address, self.port)
 
+class Handler(threading.Thread):
+    def __init__(self, queue):
+        threading.Thread.__init__(self)
+        self.q = queue
+        self.setDaemon(True)
 
-    def checkTimeout(self):
-        if self.timestamp + self.timeout < int(time.time()):
-            raise TimeoutException()
+    def run(self):
+        while True:
+            event = self.q.get()
+            try:
+                event.prepare()
+                print "Processing event %s" % str(event)
+                event.process()
+            except IllegalEventException, e:
+                print "Some failure: %s" % e.msg
 
-    def close(self):
-        self.sock.close()
+class Expirer(threading.Thread):
+    def __init__(self):
+        threading.Thread.__init__(self)
+        self.setDaemon(True)
 
+    def run(self):
+        while True:
+            print "Expiring ..."
+            currentTime = int(time.time())
+            for entry in ENTRIES.values():
+                if entry.lastEventTime != 0 and entry.lastEventTime + EVENT_LIFE_TIME < currentTime:
+                    print "Entry %s expired" % entry.dynid
+                    entry.lastEventTime = 0
+                    entry.address = NULL_ADDRESS
+                    print "Set in DNS: %s -> %s" % (entry.name, entry.address)
+            time.sleep(10)
+                                
 
+ENTRIES = {
+    'testhost': Entry('testhost,', 'test123', 'test.test.de'),
+    }
+MSG_TIME_CORRIDOR = 5
+EVENT_LIFE_TIME = 10
+NULL_ADDRESS = '0.0.0.0'
 
+q = Queue.Queue()
 
-sSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-sSock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-sSock.bind(("", 9090))
-sSock.listen(5)
-print "sSock: ", sSock.fileno()
+handler = Handler(q)
+handler.start()
 
-p = select.poll()
-p.register(sSock.fileno(), select.POLLIN)
+expirer = Expirer()
+expirer.start()
 
-clients = {}
+s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+s.bind(("", 9090))
 
 while True:
-    events = p.poll(1000)
-
-    for (fd, event) in events:
-        # print "fd: %d, event: %d" % (fd, event)
-
-        if fd == sSock.fileno() and (event & select.POLLIN):
-            # print "received connect"
-            cSock, cAddress = sSock.accept()
-            clients[cSock.fileno()] = Client(cSock, cAddress)
-            # print "cSock: %d, address: %s" % (cSock.fileno(), str(cAddress))
-            p.register(cSock.fileno(), select.POLLIN)
-        else:
-            # print "received data for ", fd
-            if event & select.POLLIN:
-                client = clients[fd]
-                try:
-                    client.process()
-                except Exception, e:
-                    print "Closing %d, %s" % (fd, str(e))
-                    client.close()
-                    del clients[fd]
-                    p.unregister(fd)
-
-    # print "clients: " + str(clients)
-    for fd in clients.keys():
-        try:
-            clients[fd].checkTimeout()
-        except TimeoutException:
-            # print "Timeout %d" % fd
-            clients[fd].close()
-            del clients[fd]
-            p.unregister(fd)
+    data, address = s.recvfrom(256)
+    try:
+        q.put_nowait(Event(address, data, int(time.time())))
+    except Queue.Full:
+        print "Event %s from %s dropped" % (data, str(address))