/FROM=address
       /NOFROM

    This qualifier controls what envelope From: address is used for
    access control probes and mailing list access probes. If the
    /FROM qualifier is omitted, then the address used for access
    checks is the postmaster return address. Specifying either
    /FROM=<> or /NOFROM tells the utility to use an empty envelope
    From: address for access checks.