ACCESSING DATA PROCESSING SYSTEMS BEHIND A NAT ENABLED NETWORK

• US 20090016369A1
• Filed: 09/23/2008
• Published: 01/15/2009
• Est. Priority Date: 10/16/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: VALLABHANENI, VASU, JAIN, VINIT, BANERJEE, DWIP N.
• Granted Patent: US 7,792,995 B2
• Time in Patent Office: Days
• US Class Current: 370/408
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/25 of the same type
• CPC Class Codes: H04L 61/2567 for reachability, e.g. inquiring the address of a correspondent behind a NAT server
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]

Abstract

A method, system, and program for accessing data processing systems behind a NAT enabled network are provided. According to one aspect of the present invention, a NAT data processing system is located behind a NAT enabled network with a NAT device as a gateway to the NAT enabled network. A client system located outside the NAT enabled network queries the NAT device for the address of the NAT data processing system located behind the NAT enabled network. The query is automatically routed through the NAT device to a DNS server. The DNS server then returns an address for the NAT data processing system and source routing for the NAT device. The NAT device forwards the address and source routing to the client system. Then, the client system sends packets to the NAT data processing system at the address with source routing through the NAT device, such that the NAT data processing system behind the NAT enabled network is directly accessed by the client system from outside the NAT enabled network.

Claims

1. A system for accessing a data processing system behind a network address translation (NAT) enabled network, comprising:

a client system communicatively connected to a public network;

a NAT device accessible to said public network and accessible to at least one NAT data processing system located in a NAT enabled network behind said NAT device;

said client system, responsive to detecting a user request to establish a connection with a domain name, wherein said domain name identifies a NAT data processing system located behind said NAT enabled network, for sending said request for said domain name to a local domain name service (DNS) server;

said client system, responsive to said local DNS server returning a fail response indicating no authoritative address for said domain name, for identifying an IP address for a NAT device associated with said requested domain name from a configuration file for a host client domain for said client system;

said client system for sending a DNS query of said domain name to said NAT device at said IP address for said NAT device;

said NAT device for automatically routing said query through said NAT device to a second DNS server that stores a plurality of private addresses for a plurality of systems located behind said NAT enabled network and a source routing address for said NAT device;

said second DNS server, responsive to receiving said query for said address of said NAT data processing system, for returning to said client system said plurality of private addresses comprising a private address for said NAT data processing system and additional separate private addresses of a plurality of parallel data processing systems providing a same service as said NAT data processing system located behind said NAT enabled network and said source routing address for said NAT device;

said client system for sending packets to said NAT data processing system at a particular address associated with said NAT data processing system from among said plurality of private addresses with loose source routing enabled through said NAT device at said source routing address, such that said NAT data processing system behind said NAT enabled network is directly accessed by said client system from outside said NAT enabled network; and

said client system, responsive to receiving a fail signal from an attempt to send packets to said NAT data processing system, for sending packets to a next data processing system from among said plurality of parallel data processing systems at one of said plurality of private addresses with loose source routing enabled through said NAT device at said source routing address.

2. The system according to claim 1 for accessing a data processing system behind a NAT enabled network wherein said second DNS server is communicatively connected to said NAT device through a pre-selected port for routing address queries.

3. The system according to claim 1 for accessing a data processing system behind a NAT enabled network, said NAT device further comprising:

means for authenticating an identity of a user using said client system;

means for only allowing access to said NAT data processing system if said authenticated identity of said user matches one of a plurality of authenticated users enabled to access systems behind said NAT enabled network.

4. A computer program product for accessing a data processing system behind a network address translation (NAT) enabled network, comprising:

a volatile or non-volatile recording medium;

means, recorded on said recording medium, responsive to detecting a user request from a client system to establish a connection with a domain name, wherein said domain name identifies a NAT data processing system located behind said NAT enabled network, for sending said request for said domain name to a local domain name service (DNS) server;

means, recorded on said recording medium, responsive to said local DNS server returning a fail response indicating no authoritative address for said domain name, for identifying an IP address for a NAT device associated with said requested domain name from a configuration file for a host client domain for said client system;

means, recorded on said recording medium for sending a DNS query of said domain name to said NAT device at said IP address for said NAT device;

means, recorded on said recording medium for automatically routing said query through said NAT device to a second DNS server that stores a plurality of private addresses for a plurality of systems located behind said NAT enabled network and a source routing address for said NAT device;

means, recorded on said recording medium, responsive to receiving said query for said address of said NAT data processing system at said DNS server, for returning from said DNS server to said client system said plurality of private addresses comprising a private address for said NAT data processing system and additional separate private addresses of a plurality of parallel data processing systems providing a same service as said NAT data processing system located behind said NAT enabled network and said source routing address for said NAT device;

means, recorded on said recording medium for sending packets, from said client system to said NAT data processing system at a particular address associated with said NAT data processing system from among said plurality of private addresses with loose source routing enabled through said NAT device at said source routing address, such that said NAT data processing system behind said NAT enabled network is directly accessed by said client system from outside said NAT enabled network; and

means, recorded on said recording medium, responsive to said client system receiving a fail signal from an attempt to send packets to said NAT data processing system, for sending packets from said client system to a next data processing system from among said plurality of parallel data processing systems at one of said plurality of private addresses with loose source routing enabled through said NAT device at said source routing address.

5. The computer program product according to claim 4 for accessing a data processing system behind a NAT enabled network wherein said means, recorded on said recording medium, for automatically routing said query through said NAT device to a DNS server, further comprises:

means, recorded on said recording medium, for automatically routing said query through a pre-selected port of said NAT device for handling DNS queries.

6. The computer program product according to claim 4 for accessing a data processing system behind a NAT enabled network further comprising:

means, recorded on said recording medium, for authenticating an identity of a user using said client system at said NAT device;

means, recorded on said recording medium, for only allowing access to said NAT data processing system if said authenticated identity of said user matches one of a plurality of authenticated users enabled to access systems behind said NAT enabled network.