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2[2]Kent S, Atkinson R. Security architecture for the internet protocol[S]. November 1998. IETF RFC 2401.
3[3]Srisuresh P, Holdrege M. IP network address translator (NAT) terminology and considerations[S]. Aug., 1999. IETF RFC 2663.
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5[5]Harkins D, Carrel D. Internet key exchange[S].November 1998. IETF RFC 2409.
6[6]Kent S, Atkinson R. IP authentication header[S]. November 1998. IETF RFC 2402.
7[7]Kent S, Atkinson R. IP encapsulating security payload(ESP)[S]. November 1998. IETF RFC 2406.
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