ssn.removeAttribute("NtlmHttpAuth");
                    }
                }
                resp.setHeader("WWW-Authenticate", "NTLM");
                if (offerBasic) {
                    resp.addHeader("WWW-Authenticate", "Basic realm=\"" + realm + "\"");
                }
                resp.setStatus(HttpServletResponse.SC_UNAUTHORIZED);

        lenient().when(request.isSecure()).thenReturn(true);

        ntlmServlet.service(request, response);

        verify(response).setHeader("WWW-Authenticate", "NTLM");
        verify(response).addHeader("WWW-Authenticate", "Basic realm=\"TestRealm\"");
        verify(response).setStatus(HttpServletResponse.SC_UNAUTHORIZED);
    }

    /**

                        ssn.removeAttribute("NtlmHttpAuth");
                    }
                }
                resp.setHeader("WWW-Authenticate", "NTLM");
                if (offerBasic) {
                    resp.addHeader("WWW-Authenticate", "Basic realm=\"" + this.realm + "\"");
                }
                resp.setStatus(HttpServletResponse.SC_UNAUTHORIZED);

{* ../../docs_src/security/tutorial003_an_py310.py hl[58:66,69:74,94] *}

/// info

The additional header `WWW-Authenticate` with value `Bearer` we are returning here is also part of the spec.

Any HTTP (error) status code 401 "UNAUTHORIZED" is supposed to also return a `WWW-Authenticate` header.

        // Execute
        NtlmPasswordAuthentication result = NtlmSsp.authenticate(mockCifsContext, mockRequest, mockResponse, challenge);

        // Verify
        assertNull(result, "Authentication result should be null");
        verify(mockResponse).setHeader("WWW-Authenticate", "NTLM");
        verify(mockResponse).setStatus(HttpServletResponse.SC_UNAUTHORIZED);

        filter.doFilter(request, response, filterChain);

        verify(response).setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        verify(response).setHeader("WWW-Authenticate", "NTLM");
        verify(response).addHeader("WWW-Authenticate", "Basic realm=\"TestRealm\"");
        verify(filterChain, never()).doFilter(any(), any());
    }

    @Test

        networkExplorer.doGet(request, response);

        verify(response).setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        verify(response).setHeader("WWW-Authenticate", "NTLM");
        verify(response).flushBuffer();
    }

    /**
     * Test doGet with NTLM authentication for directory listing

     * property values.
     *
     * @param tc
     *            context to use
     * @param domain the authentication domain
     * @param username the username to authenticate with
     * @param password the password to authenticate with
     */
    public NtlmPasswordAuthentication(final CIFSContext tc, final String domain, final String username, final String password) {

      public Authenticate() {
        client = new OkHttpClient.Builder()
            .authenticator(new Authenticator() {
              @Override public Request authenticate(Route route, Response response) throws IOException {
                if (response.request().header("Authorization") != null) {
                  return null; // Give up, we've already attempted to authenticate.
                }

In HTTP Basic Auth, the application expects a header that contains a username and a password.

If it doesn't receive it, it returns an HTTP 401 "Unauthorized" error.

And returns a header `WWW-Authenticate` with a value of `Basic`, and an optional `realm` parameter.

That tells the browser to show the integrated prompt for a username and password.