# Activity alert

The activity alert looks back over the last few seconds, minutes, hours or days, and goes off when the traffic
in that time is more, or less, than an amount you set. Turn on **Alert me**, then choose the traffic to count
(received, sent, or both), how far back to look, and the amount.

For example, to turn the computer off when a long download has finished: received, in the last 20 minutes, less
than 1 MB, then **Shut down the computer**. It also works the other way round, to tell you about unusually heavy
traffic.

### Then

Choose what DU Meter does when the alert goes off:

- **Show a message**: the alert window, with the traffic so far.
- **Send an e-mail** to the address on the [E-mail](https://www.hageltech.com/support/kb/du/using/options/email) page. Until that page holds an
  address and a mail server, this choice is greyed.
- **Disconnect VPN and dial-up connections**, **Block all network connections** or **Shut down the computer**:
  the alert window shows first, and you have 30 seconds to stop it with **Abort**. Connections stay blocked as
  long as the alert holds, after a restart too, or until you click **Stop connections blocking** in the alert
  window.