User manual

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IX. Firewall
This chapter introduces firewall general policy, access rule, and content filter settings to ensure network
security.
9.1 General Policy
The firewall is enabled by default. If the firewall is set as disabled, features such as SPI, DoS, and
outbound packet responses will be turned off automatically. Meanwhile, the remote management feature
will be activated. The network access rules and content filter will be turned off.
Firewall：
This feature allows users to turn on/off the firewall.
SPI (Stateful Packet
Inspection)：
This enables the packet automatic authentication detection technology.
The Firewall operates mainly at the network layer. By executing the
dynamic authentication for each connection, it will also perform an
alarming function for application procedure. Meanwhile, the packet
authentication firewall may decline the connections which use
non-standard communication protocol.
DoS (Denial of Service)：
This averts DoS attacks such as SYN Flooding, Smurf, LAND, Ping of
Death, IP Spoofing and so on.
Block WAN request：
If set as Enabled, then it will shut down outbound ICMP and abnormal
packet responses in connection. If users try to ping the WAN IP from the
external, this will not work because the default value is set as activated in
order to decline the outbound responses.