Network Router User Manual

ADVANCED SETUP

• SPI and Anti-DoS firewall protection (Default: Enabled) –

When the SPI (Stateful Packet Inspection) feature is turned on,

all incoming packets will be blocked except for those types

marked with a check in the Stateful Packet Inspection section.

• RIP Defect (Default: Enabled) – If an RIP request packet is not

acknowledged to by the Router, it will stay in the input queue

and not be released. Accumulated packets could cause the

input queue to fill, causing severe problems for all protocols.

Enabling this feature prevents the packets accumulating.

• Discard Ping from WAN (Default: Disabled) – Prevents the

router from responding to any PING request on the WAN port.

• Stateful Packet Inspection – This is called a “stateful” packet

inspection because it examines the contents of the packet to

determine the state of the communications; i.e., it ensures

that the stated destination computer has previously requested

the current communication. This is a way of ensuring that all

communications are initiated by the recipient computer and

are taking place only with sources that are known and trusted

from previous interactions. In addition to being more rigorous

in their inspection of packets, stateful inspection firewalls also

close off ports until connection to the specific port is

requested.

When particular types of traffic are checked, only the

particular type of traffic initiated from the internal LAN will be

allowed. For example, if the user only checks FTP Service in

the Stateful Packet Inspection section, all incoming traffic will

be blocked except for FTP connections initiated from the local

LAN.