Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

Chapter 11: DNS (Domain Name System)
Configuring hosted DNS servers
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• To delete a zone, highlight a zone and click Delete.
Secure Computing strongly recommends against deleting or modifying the
following entries:
• Any 127 reverse zones (for example, 0.1.127.in-addr.arpa). These
zones represent local loopback addresses and are required.
• The zone with 192.239 in its name. This zone provides multicast
support for the Sidewinder G2 failover feature.
There can be two different types of entries in the Zone list:
• Reverse zones (for example, 4.3.in-addr.arpa): This format indicates the
entry provides reverse lookup functions for this zone.
• Forward zones (for example, example.com): This format indicates the
entry provides forward lookup functions for this zone.
The Related Zones list displays the zones that are related to the selected
zone. For example, if a forward zone is selected, the related reverse lookup
zones are displayed. This list cannot be modified.
3 In the Zone Type field, specify whether the selected zone is a master zone,
a slave zone, or a forward zone, as follows:
• Master—A master zone is a zone for which the name server is
authoritative. Many organizations define a master zone for each subdomain
within the network. Administrators should only make changes to
zones defined as a master.
Important:You should consider defining a matching reverse zone (an
in-addr.arpa zone) for each master zone you configure.
• Slave—A slave zone is a zone for which the name server is
authoritative. Unlike a master zone, however, the slave zone’s data is
periodically transferred from another name server that is also
authoritative for the zone (usually, the master). If you select Slave, the
Master Servers field becomes active. Be sure to use the Master Servers
field to define the name server that will provide zone transfer information
for this slave zone. Administrators should not make changes to zones
defined as a slave.
Caution:When changing a zone from slave to master, the Admin Console
changes the slave file into a master file and the file becomes the lookup
manager for the zone. The DNS server will have no problems understanding
and using the new master file. For large zones (class A or B), however, this
file may become too complex to be managed properly using the Admin
Console. Secure Computing recommends either leaving large zones as
slaves on the Sidewinder G2 or manually modifying these files.
• Forward—A forward zone allows you to specify that queries for names
in the zone are forwarded to another name server.