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Using the TCP/IP port number as a service request indicator

IP.com Disclosure Number: IPCOM000013462D
Original Publication Date: 2001-Sep-16
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Abstract

Most TCP/IP proxy gateways (for example an HTTP Web proxy) between two networks operate according to the following steps:

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Using the TCP/IP port number as a service request indicator

Most TCP/IP proxy gateways (for example an HTTP Web proxy) between two networks operate according to the following steps:
1) the originating client makes a connection to the proxy
2) some proxy-specific protocol exchange happens between the client and the proxy during which the client informs the proxy where its final desired destination (on the "far side" network) is.
3) the proxy establishes a connection between itself and the remote destination
4) upon successful connection, passes packets backwards and forward between the originating client and the destination server.

     Step 2 is where the problem arises: it is not possible for a proxy to be inserted transparently into the connection path without the knowledge of the client: it has to be proxy-aware (it is noted that a SOCKSified stack is a way of mitigating this problem, but still requires proxy-awareness somewhere on the client system).

     This disclosure proposes a way for a client to be able to connect to one of a number of pre-defined remote destinations, via a proxy, without explicit knowledge of the proxy, and in particular, with no requirement for proxy-specific protocols in the client system.

     The invention solves the problem by having the proxy listen on a number of TCP/IP ports. Each port corresponds to a pre-defined remote destination. An administrator configures the "port number to destination" mappings in the proxy. The mapping consists of a listen...