User's Manual Part 2

Using SmartDefense
Chapter 9: Setting Your Security Policy 243
Small PMTU
Small PMTU (Packet MTU) is a bandwidth attack in which the client fools the
server into sending large amounts of data using small packets. Each packet has a
large overhead that creates a "bottleneck" on the server.
You can protect against this attack by specifying a minimum packet size for data
sent over the Internet.
Table 47: Small PMTU Fields
In this field… Do this…
Action
Specify what action to take when a packet is smaller than the Minimal MTU
Size threshold, by selecting one of the following:
• Block. Block the packet.
• None. No action. This is the default.
Track
Specify whether to issue logs for packets are smaller than the Minimal MTU
Size threshold, by selecting one of the following:
• Log. Issue logs. This is the default.
• None. Do not issue logs.