ZyXEL Communications ADSL 2+ Gateway P-660HW-T1 - Manual (Page 152)

P-660H/HW/W-T Series User’ Guide
Chapter 11 Firewall Configuration 152
Table 44 Firewall: Threshold
LABEL DESCRIPTION DEFAULT VALUES
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 Prestige continues to delete
half-open sessions as necessary, until the
rate of new connection attempts drops below
this number.
80 existing half-open sessions.
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
Prestige deletes half-open sessions as
required to accommodate new connection
attempts.
100 half-open sessions per minute.
The above numbers cause the
Prestige to start deleting half-open
sessions when more than 100
session establishment attempts
have been detected in the last
minute, and to stop deleting half-
open sessions when fewer than 80
session establishment attempts
have been detected in the last
minute.
Maximum
Incomplete Low
This is the number of existing half-open
sessions that causes the firewall to stop
deleting half-open sessions. The Prestige
continues to delete half-open requests as
necessary, until the number of existing half-
open sessions drops below this number.
80 existing half-open sessions.
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 Prestige 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.
100 existing half-open sessions.
The above values causes the
Prestige to start deleting half-open
sessions when the number of
existing half-open sessions rises
above 100, and to stop deleting
half-open sessions with the
number of existing half-open
sessions drops below 80.
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.
30 existing half-open TCP
sessions.
Action taken when the TCP Maximum Incomplete threshold is reached.
Delete the oldest
half open session
when new
connection
request comes
Select this radio button to clear the oldest half
open session when a new connection request
comes.