ZyXEL Communications Internet Security Gateway ZyWALL 2 Series - Manual (Page 314)

ZyWALL 2 Series User’s Guide
17-28 Remote Management Screens
17.16 Configuring Security
To change your ZyWALL’s Security settings, click REMOTE MGNT, then the Security tab. The screen
appears as shown.
If an outside user attempts to probe an unsupported port on your ZyWALL, an ICMP response packet is
automatically returned. This allows the outside user to know the ZyWALL exists. The ZyWALL series
support anti-probing, which prevents the ICMP response packet from being sent. This keeps outsiders from
discovering your ZyWALL when unsupported ports are probed.
Figure 17-24 Security
The following table describes the fields in this screen.
Table 17-8 Security
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.