ZyXEL Communications NBG-417N User Manual
Chapter 13 Firewall
NBG-417N User’s Guide
127
The following table describes the labels in this screen.
13.5 Services Screen
If an outside user attempts to probe an unsupported port on your NBG-417N, an ICMP response
packet is automatically returned. This allows the outside user to know the NBG-417N exists. Use
this screen to prevent the ICMP response packet from being sent. This keeps outsiders from
discovering your NBG-417N when unsupported ports are probed.
packet is automatically returned. This allows the outside user to know the NBG-417N exists. Use
this screen to prevent the ICMP response packet from being sent. This keeps outsiders from
discovering your NBG-417N 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.
to block and the date/time you want to block them.
Click Security > Firewall > Services. The screen appears as shown next.
Figure 77
Security > Firewall > Services
The following table describes the labels in this screen.
Table 50
Security > Firewall > General
LABEL
DESCRIPTION
Enable Firewall
Select this check box to activate the firewall. The NBG-417N performs access
control and protects against Denial of Service (DoS) attacks when the firewall is
activated.
control and protects against Denial of Service (DoS) attacks when the firewall is
activated.
Apply
Click Apply to save the settings.
Reset
Click Reset to start configuring this screen again.
Table 51
Security > Firewall > Services
LABEL
DESCRIPTION
ICMP
Internet Control Message Protocol is a message control and error-reporting
protocol between a host server and a gateway to the Internet. ICMP uses
Internet Protocol (IP) datagrams, but the messages are processed by the TCP/IP
software and directly apparent to the application user.
protocol between a host server and a gateway to the Internet. ICMP uses
Internet Protocol (IP) datagrams, but the messages are processed by the TCP/IP
software and directly apparent to the application user.
Respond to Ping
on
on
The NBG-417N will not respond to any incoming Ping requests when Disable is
selected. Select LAN to reply to incoming LAN Ping requests. Select WAN to
reply to incoming WAN Ping requests. Otherwise select LAN & WAN to reply to
all incoming LAN and WAN Ping requests.
selected. Select LAN to reply to incoming LAN Ping requests. Select WAN to
reply to incoming WAN Ping requests. Otherwise select LAN & WAN to reply to
all incoming LAN and WAN Ping requests.