This video will look at the DNS zones that are available in DNS. Once you complete watching this video you will understand zones, what zones files are available, and how you can use the different zones. Download Handout http://itfreetraining.com/handouts/dns/dnszones.pdf What is a DNS zone? A zone file contains the data for a portion of the DNS Name space. For this reason, zones allow different administrators to have control over that part of the DNS name space. Depending on what type of zone file that you create, this will determine what types of DNS records can be stored in that zone and if the data in that zone can be modified. In this video This video will look at the following zone types: Primary zone, Secondary zone, Active Directory integrated zone, Stub zone and reverse look up zone. Depending on what the needs of the administrator are, this will determine which zone file is used. Different zone files are used in different scenarios and the administrator needs to decide the correct zone file to use for that scenario. Primary zone For any domain name, there needs to be at least one primary zone. If the primary zone is stored in a text file, rather than a database like Active Directory, then this means that the server holding the primary zone text file is the only location where changes can be made to the zone data. If another zone file is asked to make changes to the zone, these changes will be forwarded to a DNS server that is holding a primary zone. This does mean that if the DNS server holding the primary server is not available, changes cannot be made. Active Directory Integrated Zone An Active Directory Integrated Zone is essentially a primary zone that has been moved from a text file stored on the computer into the Active Directory database. The advantage of this is that any Domain Controller that has the DNS role installed on it can access the Active Directory Integrated zone. Changes can also be made on any Domain Controller running DNS unlike text based primary zones which are limited to one server. Having the data stored in Active Directory means that the zone will use the same replication system that is used to replicate objects in Active Directory which is quite efficient. Active Directory Integrated Zones also allow the clients to use secure updates. Secure updates use the secure channel created when a computer is added to the domain and thus the computer must be a domain member. If you use a primary zone stored in a text file, and if you enable dynamic updates, you are also allowing none secure updates as well. Secondary Zones A secondary zone file is a copy of another zone that is read only. The copy can be any other zone stored on any other DNS server. For example, the zone file could be stored on Windows or a UNIX based system and copied from a primary or secondary zone. If you copy the data from a secondary zone, this would essentially be a copy of a copy so you may have delays waiting for the zone data to be copied from one server to the next server. Since the zone file is read only, changes cannot be made so these changes are passed onto a server holding a primary zone. Stub Zone A Stub Zone contains only the NS (Name Server) records from a zone. This NS records contain DNS servers that are considered to be authoritative for that zone. In other words, the DNS Servers are considered to be able to give the best answers for that zone. Since stub zones update the NS records, if there are changes to the NS records, these changes will updated automatically. If you use forwarding or conditional forwarding, and if changes are made, the DNS server would not be aware of these changes. The rest of the description is available at http://itfreetraining.com/dns/dns-zones See http://YouTube.com/ITFreeTraining or http://itfreetraining.com for our always free training videos. This is only one video from the many free courses available on YouTube. References "MCTS 70-640 Configuring Windows Server 2008 Active Directory Second edition" pg 455-456 "Reverse lookup" http://technet.microsoft.com/en-us/library/cc784493(v=ws.10).aspx "Reverse DNS lookup" http://en.wikipedia.org/wiki/Reverse_DNS_lookup

• published: 13 Sep 2013
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