ZyXEL Communications ZyWALL5UTM 4.0 User Manual

ZyWALL 5/35/70 Series User’s Guide

Chapter 26 DNS

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Dynamic DNS allows you to update your current dynamic IP address with one or many 
dynamic DNS services so that anyone can contact you (in NetMeeting, CU-SeeMe, etc.). You 
can also access your FTP server or Web site on your own computer using a domain name (for 
instance myhost.dhs.org, where myhost is a name of your choice) that will never change 
instead of using an IP address that changes each time you reconnect. Your friends or relatives 
will always be able to call you even if they don't know your IP address. 

First of all, you need to have registered a dynamic DNS account with www.dyndns.org. This is 
for people with a dynamic IP from their ISP or DHCP server that would still like to have a 
domain name. The Dynamic DNS service provider will give you a password or key. 

Note: You must go to the Dynamic DNS service provider’s website and register a 

user account and a domain name before you can use the Dynamic DNS 
service with your ZyWALL.

Enabling the wildcard feature for your host causes *.yourhost.dyndns.org to be aliased to the 
same IP address as yourhost.dyndns.org. This feature is useful if you want to be able to use, 
for example, www.yourhost.dyndns.org and still reach your hostname.

Note: If you have a private WAN IP address, then you cannot use Dynamic DNS.

A DNS server maps a domain name to a port's IP address. If that WAN port loses its 
connection, high availability allows the router to substitute another port's IP address for the 
domain name mapping.

To change your ZyWALL’s DDNS, click ADVANCED, DNS, then the DDNS tab. The 
screen appears as shown. Not all fields are available on all models.