Dynalink RTA1046VW User Manual

Page of 172
Wireless IAD User Manual 
 
96 
Firewall  
The firewall is a kind of software that interrupts the data between the Internet and 
your computer. It is the TCP/IP equivalent of a security gate at the entrance to your 
company. All data must pass through it, and the firewall (functions as a security 
guard) will allow only authorized data to be passed into the LAN. 
What the firewall can do? It can:   
… 
deny or permit any packet from passing through explicitly 
… 
distinguish between various interfaces and match on the following fields:   
‹ 
source and destination IP address   
‹ port 
To keep track of the performance of IP Filter, a logging device is used. The device 
supports logging of the TCP/UDP and IP packet headers and the first 129 bytes of 
the packet (including headers) whenever a packet is successfully passed through or 
blocked, and whenever a packet matches a rule being setup for suspicious packets.   
An example for firewall setup: 
 
This picture shows the most common and easiest way to employ the firewall. 
Basically, you can install a packet-filtering router at the Internet gateway and then 
configures the filter rule in the router to block or filter protocols and addresses. The 
systems behind the router usually have a direct access to the Internet; however 
some dangerous services such as NIS and NFS are usually blocked. 
For the security of your router, set the firewall is an important issue.   
Firewall – Bridge Filtering 
The bridge filtering mechanism provides a way for the users to define rules to 
allow/deny packets through the bridge based on source MAC address and/or 
destination MAC address. When bridge filtering is enabled, each packet is examined 
against the each defined filter rules sequentially, and when a matched is determined, 
the packets will be blocked. 
This page allows you to define the bridge packet filtering rules to block those 
redundant packets with specific protocols and MAC addresses. 
Choose Disabled to disable the 
bridge filtering function. Click Enabled 
to monitor and block redundant 
packets. 
To initiate the Bridge Filtering rules, 
select the Enabled radio button and 
click Apply.  
Click Add to configure a new bridge 
filtering rule. 
Note that the Add option is available 
only when there is a bridge mode PVC 
on this device.