The method 1, wherein establishing a session between the first control unit and the proxy server includes coupling through {TAIL ~ a second firewall}, {HEAD ~ the proxy server} being inside the second firewall 
through
The method 1 , wherein establishing a session between the first control unit and the proxy server includes coupling through { TAIL ~ a second firewall } , { HEAD ~ the proxy server } being inside the second firewall
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH