ZyXEL 202H 91-003-194003B Manual Do Utilizador

P-202H Plus v2 User’s Guide

Chapter 9 Firewall Configuration

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Figure 33   Firewall > Alert 

The following table describes the labels in this screen.

Table 22   Firewall > Alert

Generate alert 

when attack 

detected

Select this check box to generate an alert whenever an attack is detected. 

Denial of Service 

Thresholds

One Minute Low

This is the rate of new half-open sessions that causes the firewall to stop deleting 

half-open sessions. The ZyXEL Device continues to delete half-open sessions as 

necessary, until the rate of new connection attempts drops below this number.

One Minute High

This is the rate of new half-open sessions that causes the firewall to start deleting 

half-open sessions. When the rate of new connection attempts rises above this 

number, the ZyXEL Device deletes half-open sessions as required to 

accommodate new connection attempts.

Maximum 

Incomplete Low

This is the number of existing half-open sessions that causes the firewall to stop 

deleting half-open sessions. The ZyXEL Device continues to delete half-open 

requests as necessary, until the number of existing half-open sessions drops 

below this number.

Maximum 

Incomplete High

This is the number of existing half-open sessions that causes the firewall to start 

deleting half-open sessions. When the number of existing half-open sessions rises 

above this number, the ZyXEL Device deletes half-open sessions as required to 

accommodate new connection requests. Do not set Maximum Incomplete High 

to lower than the current Maximum Incomplete Low number.

TCP Maximum 

Incomplete 

This is the number of existing half-open TCP sessions with the same destination 

host IP address that causes the firewall to start dropping half-open sessions to that 

same destination host IP address. Enter a number between 1 and 256. As a 

general rule, you should choose a smaller number for a smaller network, a slower 

system or limited bandwidth.