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57 Cards in this Set
- Front
- Back
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Abbrev: DNS
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Domain Name System
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What type of database is used to store DNS records ?
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The DNS server stores DNS records in the form of a distributed database.
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Abbrev : AD DS
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Active Directory Domain Services
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Abbrev : DHCP
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Dynamic Host Configuration Protocol
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DHCP automatically directs all DHCP clients and servers to register their names and corresponding IP addresses with the DNS server
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DHCP automatically directs all DHCP clients and servers to register their names and corresponding IP addresses with the DNS server
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A zone represents one or more contiguous DNS domains of the DNS namespace
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An example of a DNS namespace is internal.brocadero.com.
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A server known as the authoritative server is used to store all the information relating to a particular zone. The same DNS server can be authoritative for a number of DNS zones.
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A server known as the authoritative server is used to store all the information relating to a particular zone. The same DNS server can be authoritative for a number of DNS zones.
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e procedure for transferring data from an authoritative server to a secondary server is known as a zone transfer.
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e procedure for transferring data from an authoritative server to a secondary server is known as a zone transfer.
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Windows Server 2008 supports the following types of DNS zones:
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primary
secondary integrated stub |
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The primary zone is a writeable zone, which allows the update of zone information. This zone type was part of legacy Windows Server releases.
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The primary zone is a writeable zone, which allows the update of zone information. This zone type was part of legacy Windows Server releases.
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The secondary zone is a feature of earlier Windows Server releases. It contains a full, read-only copy of primary zone data. The information in this zone can't be updated.
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The secondary zone is a feature of earlier Windows Server releases. It contains a full, read-only copy of primary zone data. The information in this zone can't be updated.
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AD integrated zones, which were introduced in Windows Server 2000, support storage of zone information in AD. Integration with AD enables users to modify resource records on any domain controller associated with the AD.
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AD integrated zones, which were introduced in Windows Server 2000, support storage of zone information in AD. Integration with AD enables users to modify resource records on any domain controller associated with the AD.
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stub zones ?
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Replication of data from one zone to another can increase network traffic. This problem is addressed through stub zones, which have just enough information to reach the relevant authoritative DNS servers.
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stub zones only store three resource record types
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the Start of Authority (SOA),
the Name Server (NS), and the Address (A) records. |
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Stub zones efficiently resolve queries between different namespaces by quickly forwarding queries to appropriate authoritative DNS servers for resolution.
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Stub zones efficiently resolve queries between different namespaces by quickly forwarding queries to appropriate authoritative DNS servers for resolution.
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New features of the DNS server in Windows Server 2008 include support for
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the DNAME resource record
read-only domain controllers (RODCs) Internet Protocol version 6 (IPv6) the GlobalNames zone |
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The DNAME resource record enables users or organizations to create aliases for multiple nodes at a time. This is known as non-terminal domain name redirection. You can use one DNAME resource record to rename a root and all its child nodes simultaneously.
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The DNAME resource record enables users or organizations to create aliases for multiple nodes at a time. This is known as non-terminal domain name redirection. You can use one DNAME resource record to rename a root and all its child nodes simultaneously.
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When a DNS server is promoted to an RODC, a read-only zone known as the primary read-only zone is created on the server. This zone stores the read-only copies of all DNS data that exists on the RODC.
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When a DNS server is promoted to an RODC, a read-only zone known as the primary read-only zone is created on the server. This zone stores the read-only copies of all DNS data that exists on the RODC.
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IPv6 supports 128-bit addresses, whereas IPv4 specifies only 32-bit addresses.
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IPv6 supports 128-bit addresses, whereas IPv4 specifies only 32-bit addresses.
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WINS
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Windows Internet Naming System
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Windows Server 2008 enables integration of the DNS server with Microsoft networking services such as WINS, AD DS, and DHCP.
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Windows Server 2008 enables integration of the DNS server with Microsoft networking services such as WINS, AD DS, and DHCP.
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ISATAP
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Intrasite Automatic Tunnel Addressing Protocol
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WPAD
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Web Proxy Auto-Discovery Protocol
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The global query block list is used to block queries from unauthorized users that have registered using dynamic updates. When the DNS server receives a resolution request, it checks if the host name is in the global query block list. If it is in the list, the DNS server doesn't resolve queries from the host.
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The global query block list is used to block queries from unauthorized users that have registered using dynamic updates. When the DNS server receives a resolution request, it checks if the host name is in the global query block list. If it is in the list, the DNS server doesn't resolve queries from the host.
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Advanced DNS server features that ship with Windows Server 2008 include
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# forwarding
# root hints # server scavenging |
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What is forwarding ?
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DNS clients send queries that contain name resolution requests to the DNS server. The DNS server first tries to resolve a name using the data available in the local network.
If no such data exists locally, the server forwards the query to a DNS server in an external network. This process is known as forwarding. |
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To use forwarding, you need to configure a DNS server to use either a
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forwarder
conditional forwarder |
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What is a forwarder ?
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A forwarder is responsible for handling all the external traffic in a network because it forwards all queries that need to be resolved to external DNS servers. The forwarder server uses its cache to attempt to resolve queries, and forwards those requests it can't resolve.
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What is a conditional forwarder ?
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Conditional forwarders are forwarders configured to forward queries for specific domain names to external DNS servers. You use conditional forwarders to resolve queries between two organizations.
For example, clients from a company called Earth Farm often access information in the brocadero.com domain. Using a conditional forwarder, Earth Farm client queries for the Brocadero domain are automatically passed to the authoritative DNS server in the brocadero.com domain for resolution. |
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Root hints are queries that enable a server to respond to requests from servers of unknown domains or domains higher than the server that receives the request.
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Root hints are queries that enable a server to respond to requests from servers of unknown domains or domains higher than the server that receives the request.
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A file named Cache.dns implements root hints for the DNS server service. It is stored in this location:
%systemroot%\System32\Dns. |
A file named Cache.dns implements root hints for the DNS server service. It is stored in this location:
%systemroot%\System32\Dns. |
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n Windows Server 2008, the server scavenging feature is used to remove old records from the zone data on a DNS server.
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n Windows Server 2008, the server scavenging feature is used to remove old records from the zone data on a DNS server.
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The value 0 is assigned to all records you add manually. The records you add are independent of aging and are not deleted automatically through scavenging.
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The value 0 is assigned to all records you add manually. The records you add are independent of aging and are not deleted automatically through scavenging.
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Scavenging removes stale records – records that have exceeded their refresh periods – from the zone data.
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Scavenging removes stale records – records that have exceeded their refresh periods – from the zone data.
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or data security reasons, aging and scavenging features are disabled by the DNS server.
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or data security reasons, aging and scavenging features are disabled by the DNS server.
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n Windows Server 2008, forwarding enables the use of external DNS servers to resolve names that DNS servers available in a network cannot resolve.
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n Windows Server 2008, forwarding enables the use of external DNS servers to resolve names that DNS servers available in a network cannot resolve.
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Root hints enable root DNS servers to locate authoritative DNS servers.
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Root hints enable root DNS servers to locate authoritative DNS servers.
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A routing table defines a set of rules to ensure that data traveling over an IP network is forwarded to the correct locations.
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A routing table defines a set of rules to ensure that data traveling over an IP network is forwarded to the correct locations.
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DNS offers two types of lookup zones:
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forward lookup
reverse lookup |
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A forward lookup zone is used to resolve domain names to their IP addresses.
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A forward lookup zone is used to resolve domain names to their IP addresses.
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A reverse lookup zone is used to identify the domain name corresponding to an IP address.
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A reverse lookup zone is used to identify the domain name corresponding to an IP address.
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You can add a forward lookup zone using the dnscmd command-line utility
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You can add a forward lookup zone using the dnscmd command-line utility
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You can reduce the workload on a DNS server by configuring it to answer requests related to local hosts and to forward requests for external domain names to an external DNS server.
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You can reduce the workload on a DNS server by configuring it to answer requests related to local hosts and to forward requests for external domain names to an external DNS server.
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Two types of queries are processed by DNS forwarding servers:
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recursive queries
iterative queries |
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recursive queries
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If the DNS server is able to resolve the client query, it sends the resolved IP address to the client.
Alternatively, if a server can't resolve a recursive query, it changes the recursive query to an iterative query by searching its list of forwarders and sending iterative queries to each one of them. |
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iterative queries
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n an iterative query, the DNS server is asked either to resolve a query or to make a best guess referral to a DNS server that may be able to resolve it.
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conditional forwarding
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You can configure a DNS server to forward queries to different forwarders according to the specific domain names that must be resolved. This is known as conditional forwarding.
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If decayed resource records are left unmanaged, they can result in problems such as
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* unnecessarily long zone transfers, if the disk space of the DNS server is filled with a large number of stale records
* degradation of the performance and response time of the DNS server with the accumulation of stale records * possible conflicts, if an IP address in a dynamic DNS environment is assigned to a different host |
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Aging and scavenging are disabled by default
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Aging and scavenging are disabled by default
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To use the aging and scavenging features, you need to enable the operations on the zone and at the DNS server.
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To use the aging and scavenging features, you need to enable the operations on the zone and at the DNS server.
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You can also enable individual resource records to be aged and scavenged by administering these records manually. This involves permitting the records to use the current (non-zero) timestamp value.
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You can also enable individual resource records to be aged and scavenged by administering these records manually. This involves permitting the records to use the current (non-zero) timestamp value.
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The scavenging and aging operations use the timestamps on resource records to determine when the records must be removed
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The scavenging and aging operations use the timestamps on resource records to determine when the records must be removed
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Zone delegation
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Zone delegation involves delegating authority for a particular subdomain to a different zone, either on the same DNS server or on another DNS server.
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zone delegation helps distribute the load of traffic among various servers, improves DNS name resolution performance, and creates a fault tolerant environment.
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zone delegation helps distribute the load of traffic among various servers, improves DNS name resolution performance, and creates a fault tolerant environment.
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The load on geographically distributed web servers is usually balanced with the help of DNS servers that implement the Round Robin technique. This option is enabled by default in Windows Server 2008.
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The load on geographically distributed web servers is usually balanced with the help of DNS servers that implement the Round Robin technique. This option is enabled by default in Windows Server 2008.
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Although Round Robin DNS is easy to implement, it has some drawbacks:
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it does not offer any failover functionality
it does not control the order in which connections are rotated |
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Disable recursion also disables forwarders
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Disable recursion also disables forwarders
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