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    HTTPDNS:Verify using a hijack simulation

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    HTTPDNS:Verify using a hijack simulation

    Last Updated:Jun 22, 2026

    Simulate a Local DNS failure to verify that HTTPDNS resolves domain names correctly after Android SDK integration.

    After you integrate the Android SDK, you can verify that HTTPDNS is working correctly by simulating a Local DNS failure.

    How it works

    HTTPDNS sends resolution requests directly to Alibaba Cloud DNS servers over HTTP or HTTPS, bypassing the system's Local DNS to prevent DNS hijacking or resolution failures caused by network issues.
    On a mobile device, Local DNS is provided by the current network: the router or carrier DNS for Wi-Fi, or the carrier DNS for mobile data. In a Wi-Fi environment, you can set the DNS to an invalid address to simulate a Local DNS resolution failure. When you make a network request in this environment:

    • If the request succeeds, it bypassed Local DNS and HTTPDNS is working correctly.

    • If the request fails, it still depends on Local DNS and the HTTPDNS integration has not taken effect.

    Prerequisites

    • Test device: An Android phone that lets you manually change Wi-Fi DNS settings.

    • Network environment: A Wi-Fi connection that lets you manually change its DNS address.

    • App status: The app is integrated with the EMAS HTTPDNS SDK.

    • Test domain name: A service domain name that is configured and used in the Alibaba Cloud HTTPDNS console.

    Procedure

    Step 1: Verify in a normal network environment

    1. Connect the test device to any available Wi-Fi network. Keep the default DNS settings.

    2. With HTTPDNS disabled, open your app and trigger a network request that uses a domain name, such as loading the home page or calling an API.

    3. Confirm that the request is successful.

    Note

    This step establishes a baseline to confirm that the app and its services work correctly under normal network conditions.

    Step 2: Simulate a Local DNS resolution failure

    1. On your test device, go to the Wi-Fi settings. Press and hold the name of the connected Wi-Fi network, and then select "Modify network" or "Advanced options".

    2. Change the IP settings to "Static".

    3. In the DNS 1 and DNS 2 fields, enter invalid IP addresses, such as 1.2.3.4 or 100.100.100.100. This ensures that the Local DNS cannot resolve domain names.

      Note

      Note: Do not use valid public DNS addresses, such as 114.114.114.114 or 8.8.8.8.

    4. Save the configuration and reconnect to the Wi-Fi network.

    Step 3: Verify in the simulated hijack environment

    1. Confirm that the device is connected to the Wi-Fi network that you modified in Step 2. The DNS for this network must be set to an invalid address.

    2. Turn off the mobile data connection. This prevents the system from automatically switching to the mobile network if the Wi-Fi connection fails.

    3. Enable HTTPDNS, open your app, and trigger the same service request as in Step 1, such as loading the home page or calling an API.

    4. Observe the request result:

      Request result

      Conclusion

      Network request succeeds

      The request bypassed Local DNS. Domain name resolution was handled by HTTPDNS, which means the integration is successful.

      Network request fails

      • If the first request fails, it might be due to a cache miss that caused a fallback to Local DNS. Wait a moment and retry.

      • If multiple requests still fail, the app still depends on Local DNS and the HTTPDNS integration has not taken effect.

      Note

      If you use a synchronous non-blocking API for domain name resolution, enable pre-resolution using the setPreResolveHosts method and allow expired IP addresses using the setEnableExpiredIp method. This ensures that resolution results are available in the local cache and prevents fallbacks to Local DNS caused by cache misses, which can affect verification accuracy.