ZyXEL Communications Prestige 652, User Manual, Page: 152 / 521

Prestige 652 Series User’s Guide
Firewall Configuration 12-5
Table 12-1 Attack Alert
LABEL DESCRIPTION
Maximum
Incomplete Low
This is the number of existing half-open sessions (default "80") 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.
Maximum
Incomplete High
This is the number of existing half-open sessions (default "100") 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. The Prestige stops deleting half-
open sessions when the number is less than the
Max Incomplete Low .
Do not set Maximum Incomplete High to lower than the current Max Incomplete
Low number.
TCP Maximum
Incomplete
This is the number of existing half-open TCP sessions (default "10") 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.
Blocking Time When TCP Maximum Incomplete is reached you can choose if the next session
should be allowed or blocked. If you select Blocking Time , any new sessions will be
blocked for the length of time you specify in the next field (min) and all old
incomplete sessions will be cleared during this period.
If you want strong security, it is better to block the traffic for a short time, as it will give
the server some time to digest the loading.
(min) Type the length of Blocking Time in minutes (1-256). The default is "0".
Back Click Back to return to the previous screen.
Apply Click Apply to save your customized settings and exit this screen.
Cancel Click Cancel to return to the previously saved settings.