Windows DNS Server Interview Questions –Part4

Windows DNS Server Interview Questions –Part4

26.What is the "in-addr.arpa" zone used for?
In a Domain Name System (DNS) environment, it is common for a user or an application to request a Reverse Lookup of a host name, given the IP address. This article explains this process. The following is quoted from RFC 1035: "The Internet uses a special domain to support gateway location and Internet address to host mapping. Other classes may employ a similar strategy in other domains. The intent of this domain is to provide a guaranteed method to perform host address to host name mapping, and to facilitate queries to locate all gateways on a particular network on the Internet.

"The domain begins at IN-ADDR.ARPA and has a substructure which follows the Internet addressing structure. "Domain names in the IN-ADDR.ARPA domain are defined to have up to four labels in addition to the IN-ADDR.ARPA suffix. Each label represents one octet of an Internet address, and is expressed as a character string for a decimal value in the range 0-255 (with leading zeros omitted except in the case of a zero octet which is represented by a single zero).

"Host addresses are represented by domain names that have all four labels specified." Reverse Lookup files use the structure specified in RFC 1035.

For example, if you have a network which is 150.10.0.0, then the Reverse Lookup file for this network would be 10.150.IN-ADDR.ARPA. Any hosts with IP addresses in the 150.10.0.0 network will have a PTR (or 'Pointer') entry in 10.150.IN- ADDR.ARPA referencing the host name for that IP address. A single IN- ADDR.ARPA file may contain entries for hosts in many domains. Consider the following scenario. There is a Reverse Lookup file 10.150.IN-ADDR.ARPA with the following contents: Exp : 1.20 IN PTR WS1.ACME.COM.

27.What are the requirements from DNS to support AD?
When you install Active Directory on a member server, the member server is promoted to a domain controller. Active Directory uses DNS as the location mechanism for domain controllers, enabling computers on the network to obtain IP addresses of domain controllers. During the installation of Active Directory, the service (SRV) and address (A) resource records are dynamically registered in DNS, which are necessary for the successful functionality of the domain controller locator (Locator) mechanism.
To find domain controllers in a domain or forest, a client queries DNS for the SRV and A DNS resource records of the domain controller, which provide the client with the names and IP addresses of the domain controllers. In this context, the SRV and A resource records are referred to as Locator DNS resource records.

When adding a domain controller to a forest, you are updating a DNS zone hosted on a DNS server with the Locator DNS resource records and identifying the domain controller. For this reason, the DNS zone must allow dynamic updates (RFC 2136) and the DNS server hosting that zone must support the SRV resource records (RFC 2782) to advertise the Active Directory directory service. For more information about RFCs, see DNS RFCs.

If the DNS server hosting the authoritative DNS zone is not a server running Windows 2000 or Windows Server 2003, contact your DNS administrator to determine if the DNS server supports the required standards. If the server does not support the required standards, or the authoritative DNS zone cannot be configured to allow dynamic updates, then modification is required to your existing DNS infrastructure.
For more information, see Checklist: Verifying DNS before installing Active Directory and Using the Active Directory Installation Wizard.

Important
The DNS server used to support Active Directory must support SRV resource records for the Locator mechanism to function. For more information, see Managing resource records. It is recommended that the DNS infrastructure allows dynamic updates of Locator DNS resource records (SRV and A) before installing Active Directory, but your DNS administrator may add these resource records manually after installation. After installing Active Directory, these records can be found on the domain controller in the following location: systemroot\System32\Config\Netlogon.dns .

28.What does a zone consist of & why do we require a zone?
Zone consists of resource records and we require zone for representing sites.

29.What is Caching Only Server?
When we install 2000 & 2003 server it is configured as caching only server where it maintains the frequently accessed sites information and again when we access the same site for next time it is obtain from cached information instead of going to the actual site.

30.What is forwarder?
When one DNS server can?t receive the query it can be forwarded to another DNS once configured as forwarder.

31.What is secondary DNS Server?
It is backup for primary DNS where it maintains a read only copy of DNS database.

32. How to enable Dynamic updates in DNS?
Start>Program>Admin tools> DNS >Zone properties.

33.What are the properties of DNS server?
INTERFACES, FORWARDERS, ADVANCED, ROUTINGS, SECURITY, MONITORING, LOGGING, DEBUG LOGGING.

34. Properties of a Zone ?
General, SOA, NAMESERVER, WINS, Security, and ZONE Transfer.

35.What is scavenging?
Finding and deleting unwanted records.