3Com OfficeConnect 3C16771 User Manual page 143

Protecting an Existing Network with the Internet Firewall 25
c Here, you want to use NTP to set the firewall time so
that the date and time are set by an atomic clock, and
are hence highly accurate. Check the box marked "Use
NTP to set time automatically".
d Type in the current date and time, in 24 hour format,
and click on the update button. This is necessary
because the Internet Firewall cannot get its date and
time from the Internet until the Internet settings are
configured, and the unit can access the Internet.
7 To specify the LAN and WAN settings, from the main
screen, click Network Settings (LAN & WAN).
a When the screen loads, from the drop-down list, select
Standard.
b In the Internet Firewall 25 Web Address field, type in
172.16.54.16
the firewall to use. Enter a LAN subnet mask of
255.255.255.0.
c In the WAN Router Address field, type
supplied by the ISP).
d In the DNS Server 1 field, type
Update. The settings are updated and the Home screen
is displayed.
8 Disable access to the NNTP (newsgroup) and IRC (Internet
Relay Chat) protocols.
The Internet Firewall 25 has a default set of access rules
that allow most basic Internet accesses (Web, FTP, HTTP,
and so forth). Users can access only those basic services
and any others that are specifically enabled.
a Click Policy to display a list of enabled network services.
You will notice that NNTP is on the list, and so
newsgroup access is currently enabled. IRC is not on this
list, but you should note that this is also enabled. In
addition to the services listed on this page, the Internet
Firewall also has a list of known services, and these are
enabled under the heading "Default". The default rule
covers all services not covered more specifically
elsewhere (for example, specifically banning IRC will
. This is the address that was freed up for
172.16.54.253
143
(as
172.16.54.1
and click