ZyXEL Communications eircom D1000, Руководство пользователя

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eircom D1000 modem U
ser’s Guide
Chapter 13 Firewall
The following table describes the labels in this screen.
Table 62
Security > Firewall > DoS > Advanced
LABEL DESCRIPTION
TCP SYN-Request
Count This is the rate of new TCP half-open sessions per second that causes the firewall to
start deleting half-open sessions. When the rate of new connection attempts rises
above this number, the Device deletes half-open sessions as required to
accommodate new connection attempts.
UDP Packet Count This is the rate of new UDP half-open sessions per second that causes the firewall to
start deleting half-open sessions. When the rate of new connection attempts rises
above this number, the Device deletes half-open sessions as required to
accommodate new connection attempts.
ICMP Echo-Request
Count This is the rate of new ICMP Echo-Request half-open sessions per second that causes
the firewall to start deleting half-open sessions. When the rate of new connection
attempts rises above this number, the Device deletes half-open sessions as required
to accommodate new connection attempts.
ICMP Redirect Select Enable to monitor for and block ICMP redirect attacks.
An ICMP redirect attack is one where forged ICMP redirect messages can force the
client device to route packets for certain connections through an attacker’s host.
DoS Log(Log Level:
DEBUG) Select Enable to log DoS attacks. See Chapter 16 on page 173 for information on
viewing logs.
Back Click this button to return to the previous screen.
Apply Click this to save your changes.
Cancel Click this to restore your previously saved settings.
13.6 Firewall Technical Reference
This section provides some technical background information about the topics covered in this
chapter.
13.6.1 Firewall Rules Overview
Your customized rules take precedence and override the Device’s default settings. The Device
checks the source IP address, destination IP address and IP protocol type of network traffic against
the firewall rules (in the order you list them). When the traffic matches a rule, the Device takes the
action specified in the rule.
Firewall rules are grouped based on the direction of travel of packets to which they apply:
• LAN to Router • WAN to LAN
• LAN to WAN • WAN to Router
Note: The LAN includes both the LAN port and the WLAN.
By default, the Device’s stateful packet inspection allows packets traveling in the following
directions:
• LAN to Router
These rules specify which computers on the LAN can manage the Device (remote management).