Setup IP address on Beagle board

Question

I want to connect a bbx15 with a device via TCP/IP. The device has a IP: 10.0.0.8; port number: 11100. I used QTcpSocket class to code:

 #include <QTcpSocket>
 mSocket = new QTcpSocket(this);
 mSocket ->connectToHost("10.0.0.8",11100);
 if(mSocket->waitForConnected(1000))
 {
   QMessageBox::information(this,"Server","Connected!");
}
else
{
    QMessageBox::critical(this,"Error",mSocket->errorString());
}

But it's still not working. I don't know how to setup the IP address to bbx15? And when I plug in cable in to socket, I couldn't boot my board until I plug out and reboot. Thank you.