Method and system in an IP network for using a network address translation (NAT) with any type of application
First Claim
1. A method to use in a first router connected on one hand to a first private Internet Protocol (IP) network and on another hand to a public IP network, for translating in a datagram a source private IP address into a public IP address so that said private IP address can be translated back into the same private IP address by a second router connected to a second private network, said method comprising the steps of:
- receiving an IP datagram from a source within a first private IP network, comprising a header including;
a source private IP address;
an IP option field;
a source TCP/UDP port number;
replacing in the IP datagram header, the source private IP address by the public IP address of the first router;
replacing in the IP datagram header the source TCP/UDP port number by the two least significant bytes of the source private IP address;
copying in the IP option field, information related to the first and the second highest significant bytes of the source private IP address so that said first and the second highest significant bytes can be deduced from said information, forwarding the IP datagram on the public IP network.
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Accused Products
Abstract
The present invention is based on a dual dynamic Network Address Translation (NAT) one Network Address Translation (NAT) is executed close to the client stations of customers (to NAT), and one Network Address Translation (NAT) is executed close to the application server (to un-NAT). The networks between the client stations and the application server, only see registered addresses (public IP addresses), while the application only sees the real private IP address. The present invention is based on a method for “NATting” and “un-NATting” the IP addresses without having to pre configure the “NATting” devices (the devices executing the operations of translating the network addresses).
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Citations
16 Claims
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1. A method to use in a first router connected on one hand to a first private Internet Protocol (IP) network and on another hand to a public IP network, for translating in a datagram a source private IP address into a public IP address so that said private IP address can be translated back into the same private IP address by a second router connected to a second private network, said method comprising the steps of:
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receiving an IP datagram from a source within a first private IP network, comprising a header including;
a source private IP address;
an IP option field;
a source TCP/UDP port number;
replacing in the IP datagram header, the source private IP address by the public IP address of the first router;
replacing in the IP datagram header the source TCP/UDP port number by the two least significant bytes of the source private IP address;
copying in the IP option field, information related to the first and the second highest significant bytes of the source private IP address so that said first and the second highest significant bytes can be deduced from said information, forwarding the IP datagram on the public IP network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method to use in a second router connected on one hand to a public Internet Protocol (IP) network and on another hand to a second private IP network, for translating in a datagram a source public IP address into a private IP address, said source private IP address having been previously translated into said source public IP address by a first router connected to a first private network, said method comprising the steps of:
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receiving from the public IP network, an IP datagram intended to be forwarded to a destination within the second private IP network, said datagram comprising a header including;
a source public IP address;
an IP option field;
a source TCP/UDP port number;
if the source public IP address has been previously translated by a first router;
replacing in the IP datagram header, the two least significant bytes of the source public IP address into the source TCP (UDP) port number;
replacing in the IP datagram header, the first and the second highest significant bytes of the source public IP address by the first and second bytes of a source IP private address deduced from information retrieved from the IP header option field;
forwarding the IP datagram to its destination within the second private IP network. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification