Library /sys$common/syshlp/nclhelp.hlb set, session_control, incoming_proxy  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Default: True          Value: True or false

    Specifies whether to honor incoming proxy requests. If this
    attribute is set to false, requests to invoke proxies on incoming
    requests are ignored.

    Example:

    set session control incoming proxy true