User's Manual

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Appendix A - Firewall
STATEFUL PACKET INSPECTION
Refers to an architecture, where the rewall keeps track of packets
on each connection traversing all its interfaces and makes sure
they are valid. This is in contrast to static packet ltering which
only examines a packet based on the information in the packet
header.
DENIAL OF SERVICE ATTACK
Is an incident in which a user or organization is deprived of the
services of a resource they would normally expect to have. Various
DoS attacks the device can withstand are ARP Attack, Ping Attack,
Ping of Death, Land, SYN Attack, Smurf Attack, and Tear Drop.
TCP/IP/PORT/INTERFACE FILTER
These rules help in the ltering of trac at the Network layer (i.e.
Layer 3).
When a Routing interface is created, Enable Firewall must be
checked.
Navigate to Advanced Setup > Security > IP Filtering.
OUTGOING IP FILTER
Helps in setting rules to DROP packets from the LAN interface.
By default, if the Firewall is Enabled, all IP trac from the LAN is
allowed. By setting up one or more lters, specic packet types
coming from the LAN can be dropped.
Example 1: Filter Name: Out_Filter1
Protocol: TCP
Source IP address: 192.168.1.45
Source Subnet Mask: 255.255.255.0
Source Port: 80
Dest. IP Address: NA
Dest. Subnet Mask: NA
Dest. Port: NA