Wednesday, April 1, 2015

Windows Server Support Interview Questions and Answers (L2)

What is the difference between Authorized DHCP and Non Authorized DHCP?
To avoid problems in the network causing by mis-configured DHCP servers, server in windows 2000 must be validate by AD before starting service to clients. If an authorized DHCP finds any DHCP server in the network it stop serving the clients

Difference between inter-site and intra-site replication. Protocols using for replication.
Intra-site replication can be done between the domain controllers in the same site. Inter-site replication can be done between two different sites over WAN links
BHS (Bridge Head Servers) is responsible for initiating replication between the sites. Inter-site replication can be done B/w BHS in one site and BHS in another site.
We can use RPC over IP or SMTP as a replication protocols where as Domain partition is not possible to replicate using SMTP

How to monitor replication
We can user Replmon tool from support tools

Brief explanation of RAID Levels
Microsoft Windows XP, Windows 2000 and Windows Server 2003 offer two types of disk storage: basic and dynamic.

Basic Disk Storage
Basic storage uses normal partition tables supported by MS-DOS, Microsoft Windows 95, Microsoft Windows 98, Microsoft Windows Millennium Edition (Me), Microsoft Windows NT, Microsoft Windows 2000, Windows Server 2003 and Windows XP. A disk initialized for basic storage is called a basic disk. A basic disk contains basic volumes, such as primary partitions, extended partitions, and logical drives. Additionally, basic volumes include multidisk volumes that are created by using Windows NT 4.0 or earlier, such as volume sets, stripe sets, mirror sets, and stripe sets with parity. Windows XP does not support these multidisk basic volumes. Any volume sets, stripe sets, mirror sets, or stripe sets with parity must be backed up and deleted or converted to dynamic disks before you install Windows XP Professional.

Dynamic Disk Storage
Dynamic storage is supported in Windows XP Professional, Windows 2000 and Windows Server 2003. A disk initialized for dynamic storage is called a dynamic disk. A dynamic disk contains dynamic volumes, such as simple volumes, spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes. With dynamic storage, you can perform disk and volume management without the need to restart Windows.

Note: Dynamic disks are not supported on portable computers or on Windows XP Home Edition-based computers.
You cannot create mirrored volumes or RAID-5 volumes on Windows XP Home Edition, Windows XP Professional, or Windows XP 64-Bit Edition-based computers. However, you can use a Windows XP Professional-based computer to create a mirrored or RAID-5 volume on remote computers that are running Windows 2000 Server, Windows 2000 Advanced Server, or Windows 2000 Datacenter Server, or the Standard, Enterprise and Data Center versions of Windows Server 2003.

Storage types are separate from the file system type. A basic or dynamic disk can contain any combination of FAT16, FAT32, or NTFS partitions or volumes.

A disk system can contain any combination of storage types. However, all volumes on the same disk must use the same storage type.

To convert a Basic Disk to a Dynamic Disk:

Use the Disk Management snap-in in Windows XP/2000/2003 to convert a basic disk to a dynamic disk. To do this, follow these steps:
1. Log on as Administrator or as a member of the Administrators group.
2. Click Start, and then click Control Panel.
3. Click Performance and Maintenance, click Administrative Tools, and then double-click Computer Management. You can also right-click My Computer and choose Manage if you have My Computer displayed on your desktop.
4. In the left pane, click Disk Management.
5. In the lower-right pane, right-click the basic disk that you want to convert, and then click Convert to Dynamic Disk. You must right-click the gray area that contains the disk title on the left side of the Details pane.
6. Select the check box that is next to the disk that you want to convert (if it is not already selected), and then click OK.
7. Click Details if you want to view the list of volumes in the disk. Click Convert.
8. Click Yes when you are prompted to convert the disk, and then click OK.

Warning: After you convert a basic disk to a dynamic disk, local access to the dynamic disk is limited to Windows XP Professional, Windows 2000 and Windows Server 2003. Additionally, after you convert a basic disk to a dynamic disk, the dynamic volumes cannot be changed back to partitions. You must first delete all dynamic volumes on the disk and then convert the dynamic disk back to a basic disk. If you want to keep your data, you must first back up the data or move it to another volume.

Dynamic Storage Terms
A volume is a storage unit made from free space on one or more disks. It can be formatted with a file system and assigned a drive letter. Volumes on dynamic disks can have any of the following layouts: simple, spanned, mirrored, striped, or RAID-5.
A simple volume uses free space from a single disk. It can be a single region on a disk or consist of multiple, concatenated regions. A simple volume can be extended within the same disk or onto additional disks. If a simple volume is extended across multiple disks, it becomes a spanned volume.
A spanned volume is created from free disk space that is linked together from multiple disks. You can extend a spanned volume onto a maximum of 32 disks. A spanned volume cannot be mirrored and is not fault-tolerant.
A striped volume is a volume whose data is interleaved across two or more physical disks. The data on this type of volume is allocated alternately and evenly to each of the physical disks. A striped volume cannot be mirrored or extended and is not fault-tolerant. Striping is also known as RAID-0.
A mirrored volume is a fault-tolerant volume whose data is duplicated on two physical disks. All of the data on one volume is copied to another disk to provide data redundancy. If one of the disks fails, the data can still be accessed from the remaining disk. A mirrored volume cannot be extended. Mirroring is also known as RAID-1.
A RAID-5 volume is a fault-tolerant volume whose data is striped across an array of three or more disks. Parity (a calculated value that can be used to reconstruct data after a failure) is also striped across the disk array. If a physical disk fails, the portion of the RAID-5 volume that was on that failed disk can be re-created from the remaining data and the parity. A RAID-5 volume cannot be mirrored or extended.
The system volume contains the hardware-specific files that are needed to load Windows (for example, Ntldr, Boot.ini, and Ntdetect.com). The system volume can be, but does not have to be, the same as the boot volume.
The boot volume contains the Windows operating system files that are located in the %Systemroot% and %Systemroot%\System32 folders. The boot volume can be, but does not have to be, the same as the system volume.

RAID 0 – Striping

RAID 1- Mirroring (minimum 2 HDD required)

RAID 5 – Striping With Parity (Minimum 3 HDD required)

RAID levels 1 and 5 only gives redundancy

What are the different backup strategies are available

Normal Backup
Incremental Backup
Differential Backup
Daily Backup
Copy Backup

What is a global catalog
Global catalog is a role, which maintains Indexes about objects. It contains full information of the objects in its own domain and partial information of the objects in other domains. Universal Group membership information will be stored in global catalog servers and replicate to all GC’s in the forest.

What is Active Directory and what is the use of it
Active directory is a directory service, which maintains the relation ship between resources and enabling them to work together. Because of AD hierarchal structure windows 2000 is more scalable, reliable. Active directory is derived from X.500 standards where information is stored is hierarchal tree like structure. Active directory depends on two Internet standards one is DNS and other is LDAP. Information in Active directory can be queried by using LDAP protocol

What is the physical and logical structure of AD?
Active directory physical structure is a hierarchal structure which fallows Forests—Trees—Domains—Child Domains—Grand Child—etc

Active directory is logically divided into 3 partitions

1.Configuration partition 2. Schema Partition 3. Domain partition 4. Application Partition (only in windows 2003 not available in windows 2000)

Out of these Configuration, Schema partitions can be replicated between the domain controllers in the in the entire forest. Where as Domain partition can be replicated between the domain controllers in the same domain

What is the process of user authentication (Kerberos V5) in windows 2000?
After giving logon credentials an encryption key will be generated which is used to encrypt the time stamp of the client machine. User name and encrypted timestamp information will be provided to domain controller for authentication. Then Domain controller based on the password information stored in AD for that user it decrypts the encrypted time stamp information. If produces time stamp matches to its time stamp. It will provide logon session key and Ticket granting ticket to client in an encryption format. Again client decrypts and if produced time stamp information is matching then it will use logon session key to logon to the domain. Ticket granting ticket will be used to generate service granting ticket when accessing network resources

What are the port numbers for Kerberos, LDAP and Global Catalog?

Kerberos – 88, LDAP – 389, Global Catalog – 3268

What is the use of LDAP (X.500 standard?)

LDAP is a directory access protocol, which is used to exchange directory information from server to clients or from server to servers

What are the problems that are generally come across DHCP?
Scope is full with IP addresses no IP’s available for new machines
If scope options are not configured properly eg default gateway
Incorrect creation of scopes etc

What is the role responsible for time synchronization?
PDC Emulator is responsible for time synchronization. Time synchronization is important because Kerberos authentication depends on time stamp information

What is TTL & how to set TTL time in DNS?
TTL is Time to Live setting used for the amount of time that the record should remain in cache when name resolution happened.

We can set TTL in SOA (start of authority record) of DNS

How to take DNS and WINS, DHCP backup
%System root%/system32/dns
%System root%/system32/WINS
%System root%/system32/DHCP

What is recovery console
Recovery console is a utility used to recover the system when it is not booting properly or not at all booting. We can perform fallowing operations from recovery console

We can copy, rename, or replace operating system files and folders
Enable or disable service or device startup the next time that start computer
Repair the file system boot sector or the Master Boot Record
Create and format partitions on drives

What is DFS & its usage

DFS is a distributed file system used to provide common environment for users to access files and folders even when they are shared in different servers physically.
There are two types of DFS domain DFS and Stand alone DFS. We cannot provide redundancy for stand alone DFS in case of failure. Domain DFS is used in a domain environment which can be accessed by /domain name/root1 (root 1 is DFS root name). Stand alone DFS can be used in workgroup environment which can be accessed through /server name/root1 (root 1 is DFS root name). Both the cases we need to create DFS root ( Which appears like a shared folder for end users) and DFS links ( A logical link which is pointing to the server where the folder is physically shared)

The maximum number of Dfs roots per server is 1.
The maximum numbers of Dfs root replicas are 31.
The maximum number of Dfs roots per domain is unlimited.
The maximum number of Dfs links or shared folders in a Dfs root is 1,000

What is RIS and what are its requirements
RIS is a remote installation service, which is used to install operation system remotely.

Client requirements
PXE DHCP-based boot ROM version 1.00 or later NIC, or a network adapter that is supported by the RIS boot disk.
Should meet minimum operating system requirements
Software Requirements
Below network services must be active on RIS server or any server in the network
Domain Name System (DNS Service)
Dynamic Host Configuration Protocol (DHCP)
Active directory “Directory” service

How many root replicas can be created in DFS?
31

What is the difference between Domain DFS and Standalone DFS?
Refer question 17.

High Level

Can we establish trust relationship between two forests?

In Windows 2000 it is not possible. In Windows 2003 it is possible

What is FSMO Roles

Flexible single master operation (FSMO) roles are
Domain Naming Master
Schema Master
PDC Emulator
Infrastructure Master
RID Master

Brief all the FSMO Roles
Windows 2000/2003 Multi-Master Model

A multi-master enabled database, such as the Active Directory, provides the flexibility of allowing changes to occur at any DC in the enterprise, but it also introduces the possibility of conflicts that can potentially lead to problems once the data is replicated to the rest of the enterprise. One way Windows 2000/2003 deals with conflicting updates is by having a conflict resolution algorithm handle discrepancies in values by resolving to the DC to which changes were written last (that is, "the last writer wins"), while discarding the changes in all other DCs. Although this resolution method may be acceptable in some cases, there are times when conflicts are just too difficult to resolve using the "last writer wins" approach. In such cases, it is best to prevent the conflict from occurring rather than to try to resolve it after the fact.
For certain types of changes, Windows 2000/2003 incorporates methods to prevent conflicting Active Directory updates from occurring.
Windows 2000/2003 Single-Master Model
To prevent conflicting updates in Windows 2000/2003, the Active Directory performs updates to certain objects in a single-master fashion.

In a single-master model, only one DC in the entire directory is allowed to process updates. This is similar to the role given to a primary domain controller (PDC) in earlier versions of Windows (such as Microsoft Windows NT 4.0), in which the PDC is responsible for processing all updates in a given domain.

In a forest, there are five FSMO roles that are assigned to one or more domain controllers. The five FSMO roles are:

Schema Master:

The schema master domain controller controls all updates and modifications to the schema. Once the Schema update is complete, it is replicated from the schema master to all other DCs in the directory. To update the schema of a forest, you must have access to the schema master. There can be only one schema master in the whole forest.
Domain naming master:

The domain naming master domain controller controls the addition or removal of domains in the forest. This DC is the only one that can add or remove a domain from the directory. It can also add or remove cross references to domains in external directories. There can be only one domain naming master in the whole forest.

Infrastructure Master:

When an object in one domain is referenced by another object in another domain, it represents the reference by the GUID, the SID (for references to security principals), and the DN of the object being referenced. The infrastructure FSMO role holder is the DC responsible for updating an object's SID and distinguished name in a cross-domain object reference. At any one time, there can be only one domain controller acting as the infrastructure master in each domain.

Note: The Infrastructure Master (IM) role should be held by a domain controller that is not a Global Catalog server (GC). If the Infrastructure Master runs on a Global Catalog server it will stop updating object information because it does not contain any references to objects that it does not hold. This is because a Global Catalog server holds a partial replica of every object in the forest. As a result, cross-domain object references in that domain will not be updated and a warning to that effect will be logged on that DC's event log. If all the domain controllers in a domain also host the global catalog, all the domain controllers have the current data, and it is not important which domain controller holds the infrastructure master role.

Relative ID (RID) Master:

The RID master is responsible for processing RID pool requests from all domain controllers in a particular domain. When a DC creates a security principal object such as a user or group, it attaches a unique Security ID (SID) to the object. This SID consists of a domain SID (the same for all SIDs created in a domain), and a relative ID (RID) that is unique for each security principal SID created in a domain. Each DC in a domain is allocated a pool of RIDs that it is allowed to assign to the security principals it creates. When a DC's allocated RID pool falls below a threshold, that DC issues a request for additional RIDs to the domain's RID master. The domain RID master responds to the request by retrieving RIDs from the domain's unallocated RID pool and assigns them to the pool of the requesting DC. At any one time, there can be only one domain controller acting as the RID master in the domain.

PDC Emulator:

The PDC emulator is necessary to synchronize time in an enterprise. Windows 2000/2003 includes the W32Time (Windows Time) time service that is required by the Kerberos authentication protocol. All Windows 2000/2003-based computers within an enterprise use a common time. The purpose of the time service is to ensure that the Windows Time service uses a hierarchical relationship that controls authority and does not permit loops to ensure appropriate common time usage.

The PDC emulator of a domain is authoritative for the domain. The PDC emulator at the root of the forest becomes authoritative for the enterprise, and should be configured to gather the time from an external source. All PDC FSMO role holders follow the hierarchy of domains in the selection of their in-bound time partner.
In a Windows 2000/2003 domain, the PDC emulator role holder retains the following functions:
Password changes performed by other DCs in the domain are replicated preferentially to the PDC emulator.
Authentication failures that occur at a given DC in a domain because of an incorrect password are forwarded to the PDC emulator before a bad password failure message is reported to the user.

Account lockout is processed on the PDC emulator.

Editing or creation of Group Policy Objects (GPO) is always done from the GPO copy found in the PDC Emulator's SYSVOL share, unless configured not to do so by the administrator.

The PDC emulator performs all of the functionality that a Microsoft Windows NT 4.0 Server-based PDC or earlier PDC performs for Windows NT 4.0-based or earlier clients.

This part of the PDC emulator role becomes unnecessary when all workstations, member servers, and domain controllers that are running Windows NT 4.0 or earlier are all upgraded to Windows 2000/2003. The PDC emulator still performs the other functions as described in a Windows 2000/2003 environment.

At any one time, there can be only one domain controller acting as the PDC emulator master in each domain in the forest.

How to manually configure FSMO Roles to separate DC’s

How can I determine who are the current FSMO Roles holders in my domain/forest?

Windows 2000/2003 Active Directory domains utilize a Single Operation Master method called FSMO (Flexible Single Master Operation), as described in Understanding FSMO Roles in Active Directory.

The five FSMO roles are:

Schema master - Forest-wide and one per forest.

Domain naming master - Forest-wide and one per forest.

RID master - Domain-specific and one for each domain.

PDC - PDC Emulator is domain-specific and one for each domain.

Infrastructure master - Domain-specific and one for each domain.

In most cases an administrator can keep the FSMO role holders (all 5 of them) in the same spot (or actually, on the same DC) as has been configured by the Active Directory installation process. However, there are scenarios where an administrator would want to move one or more of the FSMO roles from the default holder DC to a different DC. The transferring method is described in the Transferring FSMO Roles article, while seizing the roles from a non-operational DC to a different DC is described in the Seizing FSMO Roles article.

In order to better understand your AD infrastructure and to know the added value that each DC might possess, an AD administrator must have the exact knowledge of which one of the existing DCs is holding a FSMO role, and what role it holds. With that knowledge in hand, the administrator can make better arrangements in case of a scheduled shut-down of any given DC, and better prepare him or herself in case of a non-scheduled cease of operation from one of the DCs.

How to find out which DC is holding which FSMO role? Well, one can accomplish this task by many means. This article will list a few of the available methods.

Method #1: Know the default settings

The FSMO roles were assigned to one or more DCs during the DCPROMO process. The following table summarizes the FSMO default locations:

FSMO Role Number of DCs holding this role Original DC holding the FSMO role
Schema One per forest The first DC in the first domain in the forest (i.e. the Forest Root Domain)
Domain Naming One per forest
RID One per domain The first DC in a domain (any domain, including the Forest Root Domain, any Tree Root Domain, or any Child Domain)
PDC Emulator One per domain
Infrastructure One per domain

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