Method for detecting exact network type in various firewall/NAT environment

• Main Authors: SEO, JONG WON, JANG, HUN, SEO, SU MIN, LEE, SEUNG HWAN
• Format: Patent
• Language: English; Korean
• Published: 15.03.2003
• Edition: 7
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

PURPOSE: A method for inspecting Firewall/NAT(Network Address Translation) environment is provided to find out a Firewall/NAT environment of an end-user. CONSTITUTION: An end-user computer requests a TCP(Transmission Control Protocol) connection to the first checking server(1). The first checking server informs one's local port for receiving a port binding packet NPBP to a computer of the end-user(2). A network environment checking module makes the end-user computer transmit a port binding packet NPBP to a port binding address received in the above stage. The second checking server supplies a local port for receiving a port binding packet NPBP to the end-user computer(4). The first checking server transmits an acknowledgement packet to an address appended to the received port binding packet(5). If a network environment checking module is not a private IP address, the first checking server requests a TCP connection to the end-user computer(6). The first checking server transmits an address appended to the received port binding packet to the second checking server(7). The network environment checking module makes the end-user computer transmit a port binding packet NPBP to port binding address. If the port binding packet NPBP is received, the second checking server transmits an acknowledgement packet to an attached address of the end-user computer. 본 발명은 Firewall/NAT 환경 검사방법에 관한 것이다. 본 발명은 엔드-유저의 컴퓨터, 서로 다른 IP주소를 가지며 TCP 커넥션이 맺어진 제1 및 2 검사 서버를 구비한 네트워크 환경 검사시스템에서 수행되는 Firewall/NAT 환경 검사방법에 있어서, (a) 상기 엔드-유저의 컴퓨터가 상기 제1 검사 서버로 TCP 커넥션을 요청하는 단계; 및 (b) 상기 엔드-유저의 컴퓨터와 제1 검사 서버 간의 TCP 커넥션 설정이 실패하면 상기 엔드-유저의 컴퓨터가 방화벽 Ⅲ(very strict firewall)에 연결된 것으로 판단하는 단계를 포함한다. 이에 의해, 엔드-유저가 속해 있는 네트워크 환경을 알아낼 수 있게 된다. 따라서, 서비스 제공자는 엔드-유저의 Firewall/NAT 환경에 대한 적응적인 서비스를 수행할 수 있게 되며 엔드-유저 또한 자신이 속한 Firewall/NAT 환경에 따른 적응적인 서비스를 향유할 수 있게 된다.