ZyXEL Communications ZLD 37.6 DNS Overview, 37.6.1 Domain Zone Forwarder, 37.6.2 DNS Commands

Chapter 37 System

37.6 DNS Overview

DNS (Domain Name System) is for mapping a domain name to its corresponding IP address and vice versa. The DNS server is extremely important because without it, you must know the IP address of a machine before you can access it.

37.6.1 Domain Zone Forwarder

A domain zone forwarder contains a DNS server’s IP address. The ZyWALL can query the DNS server to resolve domain zones for features like VPN, DDNS and the time server. A domain zone is a fully qualified domain name without the host. For example, zyxel.com.tw is the domain zone for the www.zyxel.com.tw fully qualified domain name.

37.6.2 DNS Commands

The following table identifies the values required for many of these commands. Other input values are discussed with the corresponding commands.

Table 168 Input Values for General DNS Commands

LABEL DESCRIPTION

address_object The name of the IP address (group) object. You may use 1-31 alphanumeric characters, underscores(_), or dashes (-), but the first character cannot be a number. This value is case-sensitive.

interface_name The name of the interface.

Ethernet interface: For the ZyWALL USG 300 and above, use gex, x = 1 - N, where N equals the highest numbered Ethernet interface for your ZyWALL model.

The ZyWALL USG 200 and lower models use a name such as wan1, wan2, opt, lan1, ext-wlan, or dmz.

virtual interface on top of Ethernet interface: add a colon (:) and the number of the

virtual interface. For example: gex:y, x = 1 - N, y = 1 - 4

VLAN interface: vlanx, x = 0 - 4094

virtual interface on top of VLAN interface: vlanx:y, x = 0 - 4094, y = 1 - 12

bridge interface: brx, x = 0 - N, where N depends on the number of bridge interfaces your ZyWALL model supports.

virtual interface on top of bridge interface: brx:y, x = the number of the bridge interface, y = 1 - 4

PPPoE/PPTP interface: pppx, x = 0 - N, where N depends on the number of PPPoE/PPTP interfaces your ZyWALL model supports.

The following table describes the commands available for DNS. You must use the configure terminal command to enter the configuration mode before you can use these commands.

Table 169 Command Summary: DNS

COMMAND	DESCRIPTION
[no] ip dns server a-record fqdn w.x.y.z	Sets an A record that specifies the mapping of a fully qualified
	domain name (FQDN) to an IP address. The no command deletes
	an A record.
ip dns server cache-flush	Clears the DNS.

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