Allied Telesis AT-S63 - Manual (Page 452)

Chapter 34: Denial of Service (DoS) Defense Commands
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Caution
This defense is extremely CPU intensive and should be used with
caution. Unrestricted use can cause a switch to halt operations if the
CPU becomes overwhelmed with IP traffic. To prevent this, Allied
Telesyn recommends that you activate this defense on only one
port at a time, and only on a port where ingress fragments comprise
only a small percentage of its total traffic.
Example
The following command activates the defense on port 22:
set dos teardrop port=22 state=enable