private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
this.listBoxForwardingInterface.SelectedIndex = (int)this.numericUpDown1.Value - 1;
this.listBoxForwardingMulticast.SelectedIndex = (int)this.numericUpDown1.Value - 1;
this.listBoxForwardingPort.SelectedIndex = (int)this.numericUpDown1.Value - 1;
}