ZyXEL Communications ZyWall USG 50-H Series, User Manual

Page: 521 / 704

Chapter 36 System
ZyWALL USG 50-H User’s Guide
521
36.5.3 Address Record
An address record contains the mapping of a fully qualified domain name (FQDN) to an IP
address. An FQDN consists of a host and domain name. For example, www.zyxel.com is a
fully qualified domain name, where “www” is the host, “zyxel” is the second-level domain,
and “com” is the top level domain. mail.myZyXEL.com.tw is also a FQDN, where “mail” is
the host, “myZyXEL” is the third-level domain, “com” is the second-level domain, and “tw” is
the top level domain.
The ZyWALL allows you to configure address records about the ZyWALL itself or another
device. This way you can keep a record of DNS names and addresses that people on your
network may use frequently. If the ZyWALL receives a DNS query for an FQDN for which
the ZyWALL has an address record, the ZyWALL can send the IP address in a DNS response
without having to query a DNS name server.
36.5.4 PTR Record
A PTR (pointer) record is also called a reverse record or a reverse lookup record. It is a
mapping of an IP address to a domain name.
36.5.5 Adding an Address/PTR Record
Click the Add icon in the Address/PTR Record table to add an address/PTR record.
Figure 414 System > DNS > Address/PTR Record Edit
Action This displays whether the ZyWALL accepts DNS queries from the computer with
the IP address specified above through the specified zone (
Accept ) or discards
them ( Deny ).
Add icon Click the Add icon in the heading row to open a screen where you can add a new
rule. Refer to Table 201 on page 524 for information on the fields.
Click the Edit icon to go to the screen where you can edit the rule.
Click the Add icon in an entry to add a rule below the current entry.
Click the Delete icon to remove an existing rule. A window display asking you to
confirm that you want to delete the rule. Note that subsequent rules move up by one
when you take this action.
Click the
Move to N icon to display a field to type a number for where you want to
put that rule and press [ENTER] to move the rule to the number that you typed.
Table 197 System > DNS (continued)
LABEL DESCRIPTION