python: shutdown of communicator hangs

Hi,

in our project, we have the scenario of changing IP addresses for participants. To adapt ICE to new situations an extra thread keeps track of the actual IP and causes ICE to shut down (before the IP is changed) and restart ICE (after the IP was changed) respectively. We have a test system of more than 20 PCs (Linux), which keep proxies to each other calling time consuming functions (2s). When the address of a computer changes, sometimes the shutdown functions blocks indefiinetly. I have read in another thread that this could happen due to a deadlock when destroy() is called within a thread of the communicator (?). But this is not the case since the extra thread was createdwithin python. Are there any other reasons, why shutdown() blocks indefiinetly? I suppose this happens, when a proxy call is done via the communicator and the remote servant is not available any longer, since the remote computers IP has changed, too...

def shutdown(...):
#shutdown communicators
self._ftComS.shutdown()
self._ftComS.destroy()
self._ftComC.shutdown()
self._ftComC.destroy()
self._psCom.shutdown()
self._psCom.destroy()

def start(...):
#create communicators
self._ftComS = Ice.initialize()
self._ftComC = Ice.initialize()
self._psCom = Ice.initialize()

#register object factories
for iceId in self._ftWrapperObjectFactories:
objF = self._ftWrapperObjectFactories[iceId]
self._ftComS.addObjectFactory(objF, iceId)
self._ftComC.addObjectFactory(objF, iceId)
for iceId in self._psWrapperObjectFactories:
objF = self._psWrapperObjectFactories[iceId]
self._psComS.addObjectFactory(objF, iceId)
self._psComC.addObjectFactory(objF, iceId)

#create adapters
self._ftAdapterS = self._ftComS.createObjectAdapterWithEndpoints(
self._nRep.ID,
self._ftProt + \
' -t ' + str(int(self._timeoutMSec)) + \
' -h ' + ip + \
' -p ' + self._ftPortS
)
self._ftAdapterC = self._ftComC.createObjectAdapterWithEndpoints(
self._nRep.ID,
self._ftProt + \
' -t ' + str(self._timeoutMSec) + \
' -h ' + ip + \
' -p ' + self._ftPortC
)
self._psAdapterS = self._psCom.createObjectAdapterWithEndpoints( \
self._nRep.ID,
self._psProt + \
' -t ' + str(self._timeoutMSec) + \
' -h ' + ip + \
' -p ' + self._psPort
)
self._psAdapterC = self._psAdapterS