ZyXEL Communications P-660HN-F1A, Руководство пользователя

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Chapter 10 Firewalls
P-660HN-F1A User’s Guide
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Type of traffic for certain servers.
Reduce the threshold values if your network is slower than average for any of
these factors (especially if you have servers that are slow or handle many tasks
and are often busy).
• If you often use P2P applications such as file sharing with eMule or eDonkey, it’s
recommended that you increase the threshold values since lots of sessions will
be established during a small period of time and the P-660HN-F1A may classify
them as DoS attacks.
10.4.2 Configuring Firewall Thresholds
The P-660HN-F1A also sends alerts whenever TCP Maximum Incomplete is
exceeded. The global values specified for the threshold and timeout apply to all
TCP connections.
Click Firewall > Threshold to bring up the next screen.
Figure 81 Security > Firewall > Threshold
The following table describes the labels in this screen.
Table 57 Security > Firewall > Threshold
LABEL DESCRIPTION
Denial of Service
Thresholds The P-660HN-F1A 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-660HN-F1A
continues to delete half-open sessions as necessary, until the rate of
new connection attempts drops below this number.