まあ、たいていは問題ないです。以下のようなことで赤くなったりしちゃうので。

What events will trigger the alarm LED to go red?

The alarm LED will turn red whenever any one of the following events occur:

Emergency:
Syn Attack
Tear Drop Attack
Ping of Death

Alert:
Winnuke Attack
IP Spoof Attack
IP Source Route Attack
Land Attack
ICMP Flood
UDP Flood
Port Scan Attack
Address Sweep
Policy Deny Alarms

Check the alarm events to determine if you have received any one of these messages.