9. A method of communicating between a first computer protected by a first firewall and a second computer protected by a different second firewall, comprising the steps of: (1) at a third computer situated between the first firewall and the different second firewall, receiving a first HTTP message from the first computer through a first firewall that is configured to be open to outgoing HTTP traffic and open to incoming HTTP traffic that is responsive to and linked to outgoing HTTP traffic; (2) from the third computer, sending a first response message to the first computer through the first firewall, thereby establishing a first receive channel through the first firewall, wherein the first response message is linked to the first HTTP message; (3) at the third computer, receiving a second HTTP message from the second computer through a different second firewall that is configured to be open to outgoing HTTP traffic and open to incoming HTTP traffic that is responsive to and linked to outgoing HTTP traffic; (4) from the third computer, sending a second response message to the second computer through the second firewall, thereby establishing a second receive channel through the second firewall, wherein the second response message is linked to the second HTTP message; (5) at the third computer, receiving a third encrypted HTTP message from the first computer through the first firewall; determining that the third encrypted HTTP message is intended to be delivered to the second computer, and transmitting to the second computer the third encrypted HTTP message, wherein the third encrypted HTTP message is transmitted over the second receive channel through the second firewall to the second computer; and (6) from the third computer, periodically transmitting “keep alive” messages to the first computer over the first receive channel and to the second computer over the second receive channel to avoid a time-out condition.
9. A method of communicating between a first computer protected by a first firewall and a second computer protected by a different second firewall, comprising the steps of: (1) at a third computer situated between the first firewall and the different second firewall, receiving a first HTTP message from the first computer through a first firewall that is configured to be open to outgoing HTTP traffic and open to incoming HTTP traffic that is responsive to and linked to outgoing HTTP traffic; (2) from the third computer, sending a first response message to the first computer through the first firewall, thereby establishing a first receive channel through the first firewall, wherein the first response message is linked to the first HTTP message; (3) at the third computer, receiving a second HTTP message from the second computer through a different second firewall that is configured to be open to outgoing HTTP traffic and open to incoming HTTP traffic that is responsive to and linked to outgoing HTTP traffic; (4) from the third computer, sending a second response message to the second computer through the second firewall, thereby establishing a second receive channel through the second firewall, wherein the second response message is linked to the second HTTP message; (5) at the third computer, receiving a third encrypted HTTP message from the first computer through the first firewall; determining that the third encrypted HTTP message is intended to be delivered to the second computer, and transmitting to the second computer the third encrypted HTTP message, wherein the third encrypted HTTP message is transmitted over the second receive channel through the second firewall to the second computer; and (6) from the third computer, periodically transmitting “keep alive” messages to the first computer over the first receive channel and to the second computer over the second receive channel to avoid a time-out condition. 10. The method of claim 9 , wherein step (5) is performed at the third computer by transmitting the third encrypted HTTP message to the second computer without decrypting contents of the third encrypted HTTP message.