Firewall; Chapter 20 Firewall; Overview; What You Can Do In The Firewall Screens - ZyXEL Communications ZyWALL 1050 User Manual

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H A P T E R

20.1 Overview

Use the firewall to block or allow services that use static port numbers. Use application patrol
(see Chapter 28 on page
firewall can also limit the number of user sessions.
This figure shows the ZyWALL's default firewall rules in action and demonstrates how
stateful inspection works. User 1 can initiate a Telnet session from within the LAN zone and
responses to this request are allowed. However, other Telnet traffic initiated from the WAN or
DMZ zone and destined for the LAN zone is blocked. Communications between the WAN and
the DMZ zones are allowed. The firewall allows VPN traffic between any of the networks.

Figure 201 Default Firewall Action

20.1.1 What You Can Do in the Firewall Screens

• Use the Firewall screens
asymmetrical routes, and manage and configure firewall rules.
• Use the Session Limit screens (see
concurrent NAT/firewall sessions a client can use.
ZyWALL 1050 User's Guide
413) to control services using flexible/dynamic port numbers. The
(Section 20.2 on page
Section 20.3 on page
20

Firewall

312) to enable or disable the firewall and
316) to limit the number of
305