ZyXEL Communications Corporation P660HNT1AV2 User Manual
Chapter 14 Firewall
P-660HN-Tx(A) v2 User’s Guide
163
Anti-Probing
If an outside user attempts to probe an unsupported port on your ADSL Router, an ICMP response
packet is automatically returned. This allows the outside user to know the ADSL Router exists. The
ADSL Router supports anti-probing, which prevents the ICMP response packet from being sent. This
keeps outsiders from discovering your ADSL Router when unsupported ports are probed.
packet is automatically returned. This allows the outside user to know the ADSL Router exists. The
ADSL Router supports anti-probing, which prevents the ICMP response packet from being sent. This
keeps outsiders from discovering your ADSL Router 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.
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 ADSL Router 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.
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.