96
E
nh
an
cin
g s
ec
ur
ity
5
Select a default filter set (security
level)
In the product “Basic configuration page”, seven security
levels are defined by combining filters. When you register a
new provider, a security level is set automatically according
to the connection type (page 95). The set security level can
be changed from the “Register/Modify provider” screen.
For more details on the settings, click “Help” on the setup
screen and refer to the description displayed.
To open the “Register/Modify provider” screen
From “Basic configuration page”, click the buttons on the
setup screen in the following order:
▶
“Advanced settings” in the top page
▶
“Configure” of “Detailed basic connection setting”
▶
“Configure” of the destination of which settings you
want to change
Registering a filter
The concept of filter settings intended
for security
We recommend that you configure filter settings based on
the following point of view:
In principle, permit accesses from the LAN
to the Internet, and prohibit some accesses if
necessary
If you strictly control accesses from the LAN to the Internet,
the system would be extremely difficult to use, and it would
subsequently create problems in terms of management and
changing settings. Therefore, permit any access in principle
and, if there is a problem, only restrict access related to
the problem.
In principle, prohibit accesses from the Internet
to the LAN, and permit some accesses if
necessary
Prohibit accesses from the Internet to the LAN in principle
so that external accesses can be prevented. Permit the
external accesses only if necessary, for example, to your
public web server.
Note
The access from the Internet indicates a packet with which the
request is started from the Internet. A packet responded to a
request packet sent from the LAN has an identifier called ACK
flag, which can be differentiated from accesses from the Internet
and allowed to pass the filter.
Configuring filter settings
(Continued from the previous page)
