code: public int getLocalPort() {
  		final SIPTransaction sipTransaction = (SIPTransaction)getTransaction();
  		if(sipTransaction != null) {
  			return sipTransaction.getPort();
  		} else {
  			final String transport = JainSipUtils.findTransport(message);
  			final MobicentsExtendedListeningPoint listeningPoint = sipFactoryImpl.getSipNetworkInterfaceManager().findMatchingListeningPoint(transport, false);
  			return listeningPoint.getPort();
  		}
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipServletMessage#getLocalPort()