User`s guide

Chapter 17 Firewall
NBG6616 User’s Guide
133
4 Don't enable any local service (such as NTP) that you don't use. Any enabled service could present
a potential security risk. A determined hacker might be able to find creative ways to misuse the
enabled services to access the firewall or the network.
5 For local services that are enabled, protect against misuse. Protect by configuring the services to
communicate only with specific peers, and protect by configuring rules to block packets for the
services at specific interfaces.
6 Protect against IP spoofing by making sure the firewall is active.
7 Keep the firewall in a secured (locked) room.
17.2 General Screen
Use this screen to enable or disable the NBG6616’s firewall, and set up firewall logs. Click Security
> Firewall to open the General screen.
Figure 88 Security > Firewall > General l
The following table describes the labels in this screen.
17.3 Services Screen
If an outside user attempts to probe an unsupported port on your NBG6616, an ICMP response
packet is automatically returned. This allows the outside user to know the NBG6616 exists. Use this
screen to prevent the ICMP response packet from being sent. This keeps outsiders from discovering
your NBG6616 when unsupported ports are probed.
You can also use this screen to enable service blocking, enter/delete/modify the services you want
to block and the date/time you want to block them.
Click Security > Firewall > Services. The screen appears as shown next.
Table 57 Security > Firewall > General
LABEL DESCRIPTION
Enable Firewall Select this check box to activate the firewall. The NBG6616 performs access control and
protects against Denial of Service (DoS) attacks when the firewall is activated.
Apply Click Apply to save the settings.
Cancel Click Cancel to start configuring this screen again.