User's Manual

Chapter 52 System
ISG50 User’s Guide
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52.6.3 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 ISG50 allows you to configure address records about the ISG50 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 ISG50 receives a DNS query for an FQDN for which the ISG50 has an address
record, the ISG50 can send the IP address in a DNS response without having to query a DNS name
server.
Add Click this to create a new entry.
Edit Double-click an entry or select it and click Edit to be able to modify the entry’s
settings.
Remove To remove an entry, select it and click Remove. The ISG50 confirms you want
to remove it before doing so. Note that subsequent entries move up by one
when you take this action.
# This is the index number of the MX record.
Domain Name This is the domain name where the mail is destined for.
IP/FQDN This is the IP address or Fully-Qualified Domain Name (FQDN) of a mail server
that handles the mail for the domain specified in the field above.
Service Control This specifies from which computers and zones you can send DNS queries to the
ISG50.
Add Click this to create a new entry. Select an entry and click Add to create a new
entry after the selected entry.
Edit Double-click an entry or select it and click Edit to be able to modify the entry’s
settings.
Remove To remove an entry, select it and click Remove. The ISG50 confirms you want
to remove it before doing so. Note that subsequent entries move up by one
when you take this action.
Move To change an entry’s position in the numbered list, select the method and click
Move to display a field to type a number for where you want to put it and press
[ENTER] to move the rule to the number that you typed.
# This the index number of the service control rule. The ordering of your rules is
important as rules are applied in sequence.
The entry with a hyphen (-) instead of a number is the ISG50’s (non-
configurable) default policy. The ISG50 applies this to traffic that does not match
any other configured rule. It is not an editable rule. To apply other behavior,
configure a rule that traffic will match so the ISG50 will not have to use the
default policy.
Zone This is the zone on the ISG50 the user is allowed or denied to access.
Address This is the object name of the IP address(es) with which the computer is allowed
or denied to send DNS queries.
Action This displays whether the ISG50 accepts DNS queries from the computer with
the IP address specified above through the specified zone (Accept) or discards
them (Deny).
Table 269 Configuration > System > DNS (continued)
LABEL DESCRIPTION