12.0

23), HTTP (port 80), and HTTPS (port 443). The client computers initiate this
outbound traffic; you create a rule that permits the outbound traffic for these
protocols. Stateful inspection automatically permits the return traffic that
responds to the outbound traffic.
Stateful inspection supports all rules that direct TCP traffic.
Stateful inspection does not support the rules that filter ICMP traffic. For ICMP
traffic, you must create the rules that permit the traffic in both directions. For
example, for the clients to use the ping command and receive replies, you must
create a rule that permits ICMP traffic in both directions.
About the firewall security levels
Firewall protection provides three levels of security.
Table 14-3
Firewall security levels
DescriptionSecurity level
The Low security level allows all IP incoming traffic and outgoing traffic.
Low is the default security level.
See “About the default firewall protection” on page 133.
Low
The Medium security level enforces the Low security level. It also blocks
TCP incoming traffic and UDP stateful incoming traffic.
Medium
The High security level blocks all IP incoming traffic and outgoing traffic.High
About the default firewall protection
The default firewall protection settings are defined in the Firewall Policy. By
default, firewall protection is disabled in the policy.
When you enable firewall protection, the Symantec Firewall Policy allows all
inbound and outbound IP-based network traffic, with the following exceptions:
■ The default firewall protection blocks inbound and outbound IPv6 traffic with
all remote systems.
■ The default firewall protection restricts the inbound connections for a few
protocols that are often used in attacks (for example, Windows File Sharing).
Connections from the computers on internal networks are allowed. Connections
from the computers on external networks are blocked.
The internal networks include the following IP ranges:
■ 10.0.0.0/24
133Managing firewall protection
About the default firewall protection