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a set of local IP addresses/ports, plus
a set of remote IP addres ses/ports,
Note:
IP addresses can be a single IP address, a range of IP addresses, a
network address, or any IP address. Port numbers can be a single port
number, a range of port numbers, or any port number.
Therefore packet filtering simply defines specific sets of rules of what to
allow or disallow through a set of parameters as highlighted below:
remote devices with
IP addresses/port numbers
are
allowed
(or
disallowed
) to communicate with local devices with
IP addresses/port
numbers
over
a WAN connection
.
Examples of packet filtering requirements are:
1.
“
I want to block any outside user from being able to telnet into
my web server”.
2. “I want to disallow people in the manufacturing department to
access the Internet“.
The corresponding “transla ted” packet rules are:
1. Remote devices with
ANY IP address/port number
are
disallowed
to
communicate with the local web server (identified by its
IP address
and the
HTTP port number
) over
my Internet connection
.
2. Remote devices with
the range of IP addresse s in the
manufacturing department and any port number
are
disallowed
to
communicate with
any IP address/port number
over
my Internet
connection
.
Adding/Editing/Deleting a Packet
Rule
To add a new packet rule or to edit an existing one, select
IP Filter
from
the Configuration Menu. Then
IP Filtering Configuration
window will appear.
