Method and apparatus for sharing a single internet protocol address without a network address translation in an internet access gateway for a local network

A method of sharing a single Internet protocol address without a network address translation in an Internet access gateway for a local network, the method comprising the steps of:

• assigning a single Internet protocol address to a plurality of computers, said computers sharing the single Internet protocol address in the local network;
• checking whether an Internet protocol packet is received at the local network;
• changing a public port number using a local port number and a media access control address included in the Internet protocol packet as delimiters in a predetermined assigning manner when the Internet protocol packet is received at the local network and recording a changed public port number on a port translation table;
• checking whether an Internet protocol packet has been received at the Internet;
• and
• when the Internet protocol packet is received at the Internet, after searching the port translation table for a public port number which corresponds to a destination port number, searching for a local port number corresponding to the public port number.

A method, comprising:

• receiving a packet from a local area network including a plurality of computers;
• determining whether the packet is a multiple and broadcasting packet;
• completing work when the packet is a multiple and broadcasting packet;
• determining whether there is a new session when the packet is not a multiple and broadcasting packet;
• assigning a new port translation table entry and storing information in the entry concerning a media access control address and local port number;
• assigning of a new port number translation into an assigned port number;
• and
• transmitting the translated packet to an external network.

A method, comprising:

• receiving a packet from an external network;
• searching related port translation table with a port number;
• determining whether there is a success in searching related port translation table with the port number;
• completing procedure when there is no success in the searching;
• reading out of information of a local network from the port translation table concerning the node media access control address and local port number;
• translating of a public port number to the local port number;
• and
• transmitting the translated packet to the local network including a plurality of computers.