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3 configuring ip alias – ZyXEL Communications ZyXEL ZyWALL 5 User Manual

Page 148

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ZyWALL 5 User’s Guide

Chapter 8 DMZ Screens

147

8.3 Configuring IP Alias

IP alias allows you to partition a physical network into different logical networks over the
same Ethernet interface. The ZyWALL supports three logical DMZ interfaces via its single
physical Ethernet interface with the ZyWALL itself as the gateway for each DMZ network.

The IP alias IP addresses can be either private or public regardless of whether the physical
DMZ interface is set to use a private or public IP address. Use NAT if you want to make DMZ
computers with private IP addresses publicly accessible (see

Chapter 17 on page 283

for more

information). When you use IP alias, you can have the DMZ use both public and private IP
addresses at the same time.

Note: Make sure that the subnets of the logical networks do not overlap.

To change your ZyWALL’s IP alias settings, click DMZ, then the IP Alias tab. The screen
appears as shown.

Multicast

Select IGMP V-1 or IGMP V-2 or None. IGMP (Internet Group Multicast Protocol)

is a network-layer protocol used to establish membership in a Multicast group - it

is not used to carry user data. IGMP version 2 (RFC 2236) is an improvement

over version 1 (RFC 1112) but IGMP version 1 is still in wide use. If you would like

to read more detailed information about interoperability between IGMP version 2

and version 1, please see sections 4 and 5 of RFC 2236.

Windows

Networking

(NetBIOS over

TCP/IP)

Allow between DMZ

and LAN

Select this check box to forward NetBIOS packets from the LAN to the DMZ and

from the DMZ to the LAN. If your firewall is enabled with the default policy set to

block DMZ to LAN traffic, you also need to enable the default DMZ to LAN firewall

rule that forwards NetBIOS traffic.
Clear this check box to block all NetBIOS packets going from the LAN to the DMZ

and from the DMZ to the LAN.

Allow between DMZ

and WAN

Select this check box to forward NetBIOS packets from the WAN to the DMZ and

from the DMZ to the WAN.
Clear this check box to block all NetBIOS packets going from the WAN to the

DMZ and from the DMZ to the WAN.

Apply

Click Apply to save your changes back to the ZyWALL.

Reset

Click Reset to begin configuring this screen afresh.

Table 42 DMZ (continued)

LABEL

DESCRIPTION