ZyXEL Communications AMG1302 Manual Do Utilizador

 Chapter 15 Firewall

AMG1302/AMG1202-TSeries User’s Guide

If an outside user attempts to probe an unsupported port on your AMG1302/AMG1202-TSeries, an 
ICMP response packet is automatically returned. This allows the outside user to know the 
AMG1302/AMG1202-TSeries exists. The AMG1302/AMG1202-TSeries supports anti-probing, which 
prevents the ICMP response packet from being sent. This keeps outsiders from discovering your 
AMG1302/AMG1202-TSeries when unsupported ports are probed. 

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. 

For DoS attacks, the AMG1302/AMG1202-TSeries 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.

Use this screen to select the firewall protection level on the AMG1302/AMG1202-TSeries. Click 
Security > Firewall > General to display the following screen.

Security > Firewall > General