# Security - First Steps { #security-first-steps }

Let's imagine that you have your **backend** API in some domain.

And you have a **frontend** in another domain or in a different path of the same domain (or in a mobile application).

And you want to have a way for the frontend to authenticate with the backend, using a **username** and **password**.

We can use **OAuth2** to build that with **FastAPI**.

        // Set server timezone (in minutes) and domain
        nego.getServerData().serverTimeZone = 60; // 60 minutes
        nego.getServerData().oemDomainName = "DOMAIN";

        when(transport.getNegotiateResponse()).thenReturn(nego);

        assertEquals(60L * 1000L * 60L, handle.getServerTimeZoneOffset());
        assertEquals("DOMAIN", handle.getOEMDomainName());
        verify(session, times(2)).close();

        // Mock ServletConfig to provide initialization parameters
        Map<String, String> initParams = new HashMap<>();
        initParams.put("jcifs.smb.client.domain", "TEST_DOMAIN");
        initParams.put("jcifs.http.domainController", "dc.test.domain");
        initParams.put("jcifs.http.enableBasic", "true");
        initParams.put("jcifs.http.insecureBasic", "true");
        initParams.put("jcifs.http.basicRealm", "TestRealm");

                if (index == -1) {
                    index = user.indexOf('/');
                }
                final String domain = index != -1 ? user.substring(0, index) : defaultDomain;
                user = index != -1 ? user.substring(index + 1) : user;
                ntlm = new NtlmPasswordAuthentication(domain, user, password);
                dc = UniAddress.getByName(domainController, true);
            }
            try {

        when(mockCalledName.getNameType()).thenReturn(0x20);
        when(mockCalledName.getScope()).thenReturn("DOMAIN.COM");

        when(mockCallingName.getName()).thenReturn("CLIENT");
        when(mockCallingName.getNameType()).thenReturn(0x00);
        when(mockCallingName.getScope()).thenReturn("DOMAIN.COM");

        SessionRequestPacket packet = new SessionRequestPacket(mockConfig, mockCalledName, mockCallingName);

import org.apache.http.conn.DnsResolver;

/**
 * The {@code IdnDnsResolver} class implements the {@code DnsResolver} interface
 * to provide DNS resolution with support for Internationalized Domain Names (IDN).
 * It converts Unicode domain names to ASCII Compatible Encoding (ACE) using the
 * {@link java.net.IDN} class.
 *
 * <p>This class allows setting a custom flag for the IDN conversion and a custom
 * encoding for URL decoding.</p>

        mockName = new Name(mockConfig, "DOMAIN", 0x1B, null); // Domain Master Browser
        NbtAddress nbtAddress = new NbtAddress(mockName, testAddressInt, false, NbtAddress.H_NODE);
        assertEquals(NbtAddress.SMBSERVER_NAME, nbtAddress.firstCalledName());

        mockName = new Name(mockConfig, "DOMAIN", 0x1C, null); // Domain Controller

    /**
     * Indicates that this is an anonymous connection
     */
    int NTLMSSP_NEGOTIATE_ANONYMOUS = 0x00000800;

    /**
     * Indicates whether the OEM-formatted domain name in which the
     * client workstation has membership is supplied in the Type-1 message.
     * This is used in the negotation of local authentication.
     */
    int NTLMSSP_NEGOTIATE_OEM_DOMAIN_SUPPLIED = 0x00001000;

                assertNotNull(targetInfo);
                // Expected structure: Type (2 bytes) + Length (2 bytes) + Data (Length bytes)
                // For domain: Type 0x0002 (NetBIOS Domain Name)
                // For server: Type 0x0001 (NetBIOS Computer Name)

                // Verify domain part
                assertEquals(2, Type2Message.readUShort(targetInfo, 0)); // Type 0x0002

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

/**
 * Utility methods and classes for networking (such as IP addresses and domain names).
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 *
 * @author Craig Berry
 */
@CheckReturnValue
@NullMarked