What You Need To Know About Firewall; Firewall Rule Setup Example - ZyXEL Communications P-793H v3 User Manual

10.1.2 What You Need to Know About Firewall

DoS
Denials of Service (DoS) attacks are aimed at devices and networks with a connection to the
Internet. Their goal is not to steal information, but to disable a device or network so users no longer
have access to network resources. The ZyXEL Device is pre-configured to automatically detect and
thwart all known DoS attacks.
Anti-Probing
If an outside user attempts to probe an unsupported port on your P-79X, an ICMP response packet
is automatically returned. This allows the outside user to know the P-79X exists. The P-79X
supports anti-probing, which prevents the ICMP response packet from being sent. This keeps
outsiders from discovering your P-79X 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 P-79X 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.
Finding Out More
• See Section 10.1.3 on page 100
• See Section 10.5 on page 110

10.1.3 Firewall Rule Setup Example

The following Internet firewall rule example allows a hypothetical "MyService" connection from the
Internet.
Click Security > Firewall > Rules.
1
Select WAN to LAN in the Packet Direction field.
2
Chapter 10 Firewalls
for an example of setting up a firewall.
for advanced technical information on firewall.
P-79X Series User's Guide
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