| 摘要 |
Traffic from a client 1 to a server 4 is tunnelled through firewall 2 using HTTP requests for data from behind the firewall and HTTP responses for data going through the firewall from outside. Means are also provided for maintaining a stock of pending HTTP requests at an HTTP server 4 so that a HTTP response is always available for traffic into the network protected by the firewall. In an embodiment there is provided a network node implementing a TCP/IP protocol stack and a HTTP client, wherein the stack supplies packet data and if the data is destined for a predetermined address or port the data is passed to the HTTP client (rather than the physical layer), and the HTTP client is configured to encapsulate the packet data in a HTTP request to send to the server. The HTTP request would be able to pass through a restrictive firewall 2 on a normal, unrestricted, HTTP port. In a further embodiment a network node comprises HTTP server means which receives data encapsulated in HTTP requests and defers sending a response to the request until packet data, for the sender of the request, has been supplied from a request from another client.
|
