P-662H/HW-D Series User’s Guide

Table 71 Firewall: Threshold (continued)

LABEL

DESCRIPTION

DEFAULT VALUES

 

 

 

Maximum

This is the number of existing half-open

80 existing half-open sessions.

Incomplete Low

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

This is the number of existing half-open

100 existing half-open sessions.

Incomplete High

sessions that causes the firewall to start

The above values causes the

 

deleting half-open sessions. When the

ZyXEL Device to start deleting half-

 

number of existing half-open sessions rises

open sessions when the number of

 

above this number, the ZyXEL Device deletes

existing half-open sessions rises

 

half-open sessions as required to

above 100, and to stop deleting

 

accommodate new connection requests. Do

half-open sessions with the

 

not set Maximum Incomplete High to lower

number of existing half-open

 

than the current Maximum Incomplete Low

sessions drops below 80.

 

number.

 

TCP Maximum

This is the number of existing half-open TCP

30 existing half-open TCP

Incomplete

sessions with the same destination host IP

sessions.

 

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.

 

Action taken when the TCP Maximum Incomplete threshold is reached.

 

 

 

Delete the oldest

Select this radio button to clear the oldest half

 

half open session

open session when a new connection request

 

when new

comes.

 

connection

 

 

request comes

 

 

Deny new

Select this radio button and specify for how

 

connection

long the ZyXEL Device should block new

 

request for

connection requests when TCP Maximum

 

 

Incomplete is reached.

 

 

Enter the length of blocking time in minutes

 

 

(between 1 and 256).

 

Apply

Click Apply to save your changes back to the ZyXEL Device.

 

 

Cancel

Click Cancel to begin configuring this screen afresh.

 

 

 

Chapter 11 Firewall Configuration

201