ZyXEL P-660HW-67 User Guide - Page 165

Anti-Probing, DoS Thresholds

Page 165 highlights

Chapter 10 Firewall can be carried out through ICMPv6. Since ICMPv6 error messages are critical for establishing and maintaining communications, filtering policy focuses on ICMPv6 informational messages. Anti-Probing If an outside user attempts to probe an unsupported port on your ZyXEL Device, an ICMP response packet is automatically returned. This allows the outside user to know the ZyXEL Device exists. The ZyXEL Device supports anti-probing, which prevents the ICMP response packet from being sent. This keeps outsiders from discovering your ZyXEL Device when unsupported ports are probed. ICMP Internet Control Message Protocol (ICMP) 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. DoS Thresholds For DoS attacks, the ZyXEL Device uses thresholds to determine when to drop sessions that do not become fully established. These thresholds apply globally to all sessions. You can use the default threshold values, or you can change them to values more suitable to your security requirements. ADSL Router Series User's Guide 165

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Chapter 10 Firewall
ADSL Router Series User’s Guide
165
can be carried out through ICMPv6. Since ICMPv6 error messages are critical for establishing and
maintaining communications, filtering policy focuses on ICMPv6 informational messages.
Anti-Probing
If an outside user attempts to probe an unsupported port on your ZyXEL Device, an ICMP response
packet is automatically returned. This allows the outside user to know the ZyXEL Device exists. The
ZyXEL Device supports anti-probing, which prevents the ICMP response packet from being sent.
This keeps outsiders from discovering your ZyXEL Device when unsupported ports are probed.
ICMP
Internet Control Message Protocol (ICMP) 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.
DoS Thresholds
For DoS attacks, the ZyXEL Device uses thresholds to determine when to drop sessions that do not
become fully established. These thresholds apply globally to all sessions. You can use the default
threshold values, or you can change them to values more suitable to your security requirements.