Abstract: In a computer implemented method, packets are transparently and securely communicated between a trusted computer and an untrusted computer connected by a gateway. Each packet including a source address, a destination address and a payload. The gateway, according to rules stored in a configuration database, intercepts a packet received in an Internet protocol layer of the gateway. The packet has a source address of the trusted computer, a destination address of the untrusted computer and a first payload. The intercepted packet is diverted to a proxy server operating in an application protocol layer of the gateway. The intercepted packet is consumed by the proxy server, and the proxy server generates a second packet having a source address of the gateway and the destination address of the untrusted computer and the first payload. The second packet is sent to the untrusted computer to enable the trusted computer to communicate with the untrusted computer securely.