Why Does My Android Ping App Fail to Ping External IPs?

Pinging External IPs from Java Android

In developing a Ping application for Android, it's common to encounter issues when attempting to ping external servers. While local IP pinging may work, accessing external IP addresses poses certain challenges.

One potential cause for this problem can be related to the accessibility of the external server. To check this, consider modifying your code to ping different external servers, such as 8.8.8.8 (Google DNS) or 1.1.1.1 (Cloudflare DNS). This will help determine if the issue lies with the specific external IP you're targeting or with your code.

If you've verified the external server's accessibility and the problem persists, examine your code's syntax closely. The InetAddress.isReachable() method takes two parameters: the IP address to ping and a timeout value. Ensure that you have set an appropriate timeout value that allows sufficient time for the ping operation to complete.

Additionally, ensure that you have declared the necessary permissions in your application's manifest. You should explicitly declare the android.permission.INTERNET permission, which allows your application to make network connections.

If you have checked all these aspects and the issue still persists, consider using a different approach to perform external IP pings. One method that has been successfully used involves executing a shell command via the Runtime.exec() method. Here's an example code snippet that demonstrates this approach:

private boolean executeCommand(){
    System.out.println("executeCommand");
    Runtime runtime = Runtime.getRuntime();
    try
    {
        Process  mIpAddrProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int mExitValue = mIpAddrProcess.waitFor();
        System.out.println(" mExitValue "+mExitValue);
        if(mExitValue==0){
            return true;
        }else{
            return false;
        }
    }
    catch (InterruptedException ignore)
    {
        ignore.printStackTrace();
        System.out.println(" Exception:"+ignore);
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
        System.out.println(" Exception:"+e);
    }
    return false;
}

This code snippet uses the Runtime.exec() method to execute the /system/bin/ping command, which allows you to ping an external IP address specifically. The -c 1 option specifies that only a single ping request should be sent. The method returns a boolean value indicating whether the ping was successful (true) or not (false).

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