%% You should probably cite rfc2709 instead of this I-D.
@techreport{ietf-nat-security-02,
    number =    {draft-ietf-nat-security-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-nat-security/02/},
    author =    {Pyda Srisuresh},
    title =     {{Security Model with Tunnel-mode IPsec for NAT Domains}},
    pagetotal = 11,
    year =      1999,
    month =     aug,
    day =       19,
    abstract =  {This document describes a security model by which tunnel-mode IPsec security can be architected on NAT devices. This memo provides information for the Internet community.},
}