NetComm NB6PLUS4WN, NB6, NB6W, NB6PLUS4, NB6PLUS4W Firewall, An example for firewall setup

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:

PC 1

Internet

Router

PC 2

with Firewall Protection

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, setting the firewall is an important issue.

YML854 Rev1	NB6, NB6W, NB6Plus4, NB6Plus4W, NB6Plus4Wn User Guide
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