@techreport{sparks-sip-multiproxy-auth-00,
    number =    {draft-sparks-sip-multiproxy-auth-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-sparks-sip-multiproxy-auth/00/},
    author =    {Robert Sparks},
    title =     {{Providing for Multiple-Proxy Authentication of a SIP Request}},
    pagetotal = 4,
    year =      1999,
    month =     oct,
    day =       21,
    abstract =  {SIP/2.0 as specified in RFC2543 provides a mechanism for a proxy involved in a SIP transaction to authenticate the originator of the request. Unfortunately, this mechanism is not well defined when more than one proxy in a request’s path desires such authentication. This draft proposes a mechanism that would allow authentication in that scenario to work as expected. Under this proposal, SIP clients would issue requests with multiple Proxy-Authorization headers, one for each challenge it has seen in the lifetime of a given call leg. Authenticating SIP proxies would search each request for a Proxy- Authorization response to its own challenge, passing any others downstream unaltered.},
}