Chapter 10 Firewalls
P-79X Series User’s Guide
109
Figure 64 Security > Firewall > Threshold
The following table describes the labels in this screen.
Table 38 Security > Firewall > Threshold
LABEL DESCRIPTION
Denial of Service
Thresholds
The P-79X measures both the total number of existing half-open sessions and
the rate of session establishment attempts. Both TCP and UDP half-open
sessions are counted in the total number and rate measurements.
Measurements are made once a minute.
One Minute Low
This is the rate of new half-open sessions per minute that causes the firewall to
stop deleting half-open sessions. The P-79X 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 per minute that causes the firewall to
start deleting half-open sessions. When the rate of new connection attempts
rises above this number, the P-79X deletes half-open sessions as required to
accommodate new connection attempts.
For example, if you set the one minute high to 100, the P-79X starts deleting
half-open sessions when more than 100 session establishment attempts have
been detected in the last minute. It stops deleting half-open sessions when the
number of session establishment attempts detected in a minute goes below the
number set as the one minute low.
Maximum
Incomplete Low
This is the number of existing half-open sessions that causes the firewall to stop
deleting half-open sessions. The P-79X 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 P-79X 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.
For example, if you set the maximum incomplete high to 100, the P-79X starts
deleting half-open sessions when the number of existing half-open sessions
rises above 100. It stops deleting half-open sessions when the number of
existing half-open sessions drops below the number set as the maximum
incomplete low.
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