Services Screen - ZyXEL Communications NBG6503 User Manual

17.5 Services Screen

If an outside user attempts to probe an unsupported port on your NBG, an ICMP response packet is
automatically returned. This allows the outside user to know the NBG exists. Use this screen to
prevent the ICMP response packet from being sent. This keeps outsiders from discovering your NBG
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.
Figure 94 Security > Firewall > Services
The following table describes the labels in this screen.
Table 56 Security > Firewall > Services
LABEL
ICMP
Respond to
Ping on
Apply
Chapter 17 Firewall
DESCRIPTION
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.
The NBG 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.
Click Apply to save the settings.
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