User manual

Network Setup
105
DNS proxy
The CyberGuard SG appliance can also be configured to run a domain name server
(DNS) proxy. The CyberGuard SG appliance passes incoming DNS requests from
internal clients to an external DNS server, and forwards the reply back to the internal
client.
If this is enabled, all the computers on the LAN can specify the IP address of the
CyberGuard SG appliance as their DNS server.
Check Enable DNS proxy to enable this feature. If you are using the CyberGuard SG
appliance’s DHCP server, you may also check Update DNS with local DHCP leases.
This allows the CyberGuard SG appliance’s DNS proxy to look up the names of devices
that have requested IP address addresses.
Dynamic DNS
A dynamic DNS service is useful when you don’t have a static Internet IP address, but
need to remain contactable by hosts on the Internet. Dynamic DNS service providers
such as TZO.com and dyndns.org can register an Internet domain name that points to
your Internet IP address no matter how often it changes.
Whenever its Internet IP address changes, the CyberGuard SG appliance alerts the
dynamic DNS service provider and the domain name records are updated appropriately.
First, create an account with the dynamic DNS service provider of your choice, then
select this service provider from the Service pull down menu and click New.