ZyXEL Communications ZyXEL ZyWALL 5 - Manual (Page 328)

ZyWALL 5 User’s Guide
Chapter 20 DNS 327
Figure 160 DNS LAN
The following table describes the labels in this screen.
Table 116 DNS LAN
LABEL DESCRIPTION
DNS Servers
Assigned by DHCP
Server
The ZyWALL passes a DNS (Domain Name System) server IP address (in the
order you specify here) to the DHCP clients. The ZyWALL only passes this
information to the LAN DHCP clients when you select the DHCP Server check
box. When you clear the DHCP Server check box, DHCP service is disabled
and you must have another DHCP sever on your LAN, or else the computers
must have their DNS server addresses manually configured.
First DNS Server
Second DNS Server
Third DNS Server Select From ISP if your ISP dynamically assigns DNS server information (and
the ZyWALL's WAN IP address). Use the drop-down list box to select a DNS
server IP address that the ISP assigns in the field to the right.
Select User-Defined if you have the IP address of a DNS server. Enter the DNS
server's IP address in the field to the right. If you chose User-Defined, but leave
the IP address set to 0.0.0.0, User-Defined changes to None after you click
Apply. If you set a second choice to User-Defined, and enter the same IP
address, the second User-Defined changes to None after you click Apply.
Select DNS Relay to have the ZyWALL act as a DNS proxy. The ZyWALL's LAN
IP address displays in the field to the right (read-only). The ZyWALL tells the
DHCP clients on the LAN that the ZyWALL itself is the DNS server. When a
computer on the LAN sends a DNS query to the ZyWALL, the ZyWALL forwards
the query to the ZyWALL's system DNS server (configured in the DNS System
screen) and relays the response back to the computer. You can only select DNS
Relay for one of the three servers; if you select DNS Relay for a second or third
DNS server, that choice changes to None after you click Apply.
Select None if you do not want to configure DNS servers. If you do not configure
a DNS server, you must know the IP address of a computer in order to access it.
Apply Click Apply to save your changes back to the ZyWALL.
Reset Click Reset to begin configuring this screen afresh.