ZyXEL Communications NBG420N - Manual (Page 156)

Chapter 13 Firewall
NBG420N User’s Guide
156
13.4 Services Screen
Click Security > Firewall > Services. The screen appears as shown next.
If an outside user attempts to probe an unsupported port on your NBG420N, an ICMP
response packet is automatically returned. This allows the outside user to know the NBG420N
exists. Use this screen to prevent the ICMP response packet from being sent. This keeps
outsiders from discovering your NBG420N 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.
Figure 98 Security > Firewall > Services
The following table describes the labels in this screen.
Log Select whether to create a log for packets that are traveling in the selected
direction when the packets are blocked (Log All) or forwarded (Log Forward). Or
select Not Log to not log any records.
To log packets related to firewall rules, make sure that Access Control under Log
is selected in the Logs > Log Settings screen.
Apply Click Apply to save the settings.
Reset Click Reset to start configuring this screen again.
Table 57 Security > Firewall > General
LABEL DESCRIPTION
Table 58 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.
Respond to Ping
on
The NBG420N 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.