Chapter 8 Dmz Screens; Dmz Overview; Configuring Dmz - ZyXEL Communications ZyWall 35 User Manual

This chapter describes how to configure the ZyWALL's DMZ.

8.1 DMZ Overview

The DeMilitarized Zone (DMZ) auto-negotiating 10/100 Mbps Ethernet port provides a way
for public servers (Web, e-mail, FTP, etc.) to be visible to the outside world (while still being
protected from DoS (Denial of Service) attacks such as SYN flooding and Ping of Death).
These public servers can also still be accessed from the secure LAN.
By default the firewall allows traffic between the WAN and the DMZ, traffic from the DMZ to
the LAN is denied, and traffic from the LAN to the DMZ is allowed. Internet users can have
access to host servers on the DMZ but no access to the LAN, unless special filter rules
allowing access were configured by the administrator or the user is an authorized remote user.
It is highly recommended that you connect all of your public servers to the DMZ port. If you
have more than one public server, connect a hub to the DMZ port.
It is also highly recommended that you keep all sensitive information off of the public servers
connected to the DMZ port. Store sensitive information on LAN computers.

8.2 Configuring DMZ

The DMZ port and the computers connected to it can have private or public IP addresses.
When the DMZ uses public IP addresses, the WAN and DMZ ports must use public IP
addresses that are on separate subnets. See
subnetting. If you do not configure SUA NAT or any full feature NAT mapping rules for the
public IP addresses on the DMZ, the ZyWALL will route traffic to the public IP addresses on
the DMZ without performing NAT. This may be useful for hosting servers for NAT unfriendly
applications (see
If the DMZ computers use private IP addresses, use NAT if you want to make them publicly
accessible.
Unlike the LAN, the ZyWALL does not assign TCP/IP configuration via DHCP to computers
connected to the DMZ port(s). Manually assign the computers static IP addresses (in the same
subnet as the DMZ port's IP address), DNS server addresses and the ZyWALL's DMZ IP
address as the default gateway.

Chapter 8 DMZ Screens

Chapter 17 on page 293
C
H A P T E R
DMZ Screens
Appendix C on page 591
for more information).
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