%% You should probably cite draft-ietf-mip4-vpn-problem-solution instead of this I-D.
@techreport{ietf-mobileip-vpn-problem-solution-03,
    number =    {draft-ietf-mobileip-vpn-problem-solution-03},
    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-mobileip-vpn-problem-solution/03/},
    author =    {Sami Vaarala},
    title =     {{Mobile IPv4 Traversal Across IPsec-based VPN Gateways}},
    pagetotal = 49,
    year =      2003,
    month =     sep,
    day =       30,
    abstract =  {This document outlines the proposed solution for the Mobile IPv4 and IPsec coexistence problem for enterprise users. The solution consists of an applicability statement for using Mobile IPv4 and IPsec for session mobility in corporate remote access scenarios, and a required mechanism for detecting the trusted internal network securely. The solution requires only changes to the mobile node; changes to Mobile IPv4 or IPsec are not required.},
}