Configuring and Managing the DHCP Server Role
DHCP is a simple, standard protocol that makes TCP/IP network configuration much easier for the administrator by dynamically assigning IP addresses and providing additional configuration information to DHCP clients automatically. It is based heavily on BOOTP but rather than pushing preconfigured parameters to the expected clients, DHCP can dynamically allocate and reclaim IP addresses from a pool of IP addresses. DHCP is an open, industry-standard protocol reducing the complexity of administering networks based on TCP/IP. It is defined by IEFT (Internet Engineering Task Force) in RFC (Request for Comments) 2131 and 2132. DHCP functions at the application layer of the OSI (Open System Interconnection) model, as defined by ISO (International Organizations for Standardization) and the ITU-T (International Telecommunication union ) Telecommunications Standards Section.
Four Key Benefits of DHCP
• Centralized administration of IP configuration
• Dynamic host configuration
• Seamless IP host configuration
• Flexibility and scalability
Additional configuration information is provided in the form of options and can be associated with reserved IPs to a vendor or user class, to a scope, or to an entire DHCP server.
APIPA is useful for providing addresses to single-segment networks that do not have a DHCP server.
DHCP Terminology
• DHCP client – Computer on the network obtaining information from the DHCP server.
• DHCP server – Computer on the network providing DHCP configuration to clients.
• DHCP lease – This defines the duration for which the DHCP lease to the client. The lease duration can be between 1 minute and 999 days. The default lease is eight days.
DHCP Message Types
• DHCPDISCOVER – Sent by the client to locate a DHCP Server.
• DHCPOFFER – Sent by the DHCP server in response to DHCPDICOVER with the offered configuration parameters.
• DHCPREQUEST – Sent by the client to signal acceptance of the offer (DHCPOFFER) from the DHCP server.
• DHCPDECLINE – Sent by the client to the DHCP Server, informing that the offer has been declined.
• DHCPACK – Sent by the DHCP server to the client to confirm.
• DHCPNACK - Sent by the DHCP server to the client to deny the DHCPREQUEST.
• DHCPRELEASE - Sent by the client to a DHCP server to relinquish an IP address and cancel the remaining lease.
• DHCPINFORM - Sent by the client to a DHCP server to ask only for additional local configuration parameters.
D.O.R.A. Discover (DHCPDISCOVER), Offer (DHCPOFFER), Request (DHCPREQUEST), Acknowledge (DHCPACK) is the process between the client and the DHCP server.
DHCP Scope The Scope determines which IP Addresses are allocated to clients. You can configure as many scopes on a DHCP server as needed for your environment.
DHCP Reservation: These are reserved IP addresses for hosts that need to have a static IP address. Examples are e-mail servers, and application servers. These are set up using the MAC address of the DHCP client computer so only the client with that address will get that reserved address.
DHCP Maintenance: Because DHCP is a key component in your organization, you must manage and monitor it. DHCP management consists of backing up and restoring the database as well as reconciling, compacting, and, in some cases, removing the database.
Sunday, March 7, 2010
Wednesday, March 3, 2010
Lesson 2
Installing Microsoft Windows Server 2008
Installing and Initial Server Configuration:
Best practices when installing Windows Server 2008 recommends installing the software onto which type of media fresh (media that has never been used before) or previously used media(media containing existing files). If Windows Server 2008 is installed onto a disk partition containing a previous version of Windows, the files will be preserved but the software will not be usable. Note: The Windows Server 2008 distribution media contains a bootable system that can be used for a standalone software installation or to repair an existing installation.
Once you have installed Windows 2008 Server the software will automatically launch the ICT Initial Configuration Tasks. You should go through all of these tasks (Administrator password, time zone, windows update, networks settings, adding server roles and features …). Note: By default, the Windows Firewall is turned on. It is also especial important to download and apply any that have been released since the creation of the media you are using to install.
When setting up your network connection keep in mind a server usually has a static IP address so you will also need to manually setup the DNS address information.
Network discovery finds and accesses other computer and resources shared on the network. Warning if you inappropriately allow network discovery in a public network such as at a wireless café, you would be allowing anyone to access file shares on your system.
Configuring Server Roles:
To improve security and manageability of Windows 2008 Servers you use the Server Manager console to install one or multiple server roles. To reduce the attach surface on Windows 2008 computers, system files(executables and DLL files) associated with a particular role will not be installed on a server until not be install until the role is installed, instead of leaving unused software lying dormant on the server as a potential target for a network virus or worm. This also keeps the system/server cleaner to run these applications.
Configuring Server Storage:
Windows Server 2008 (and all Microsoft operating systems going back to Windows 2000) supports which two types of hard disks, basic and dynamic.
Basic disks use partition tables that are recognized and supported by older operating systems. All disks in a windows 2008 server start out as basic until they are converted to dynamic disks.
Dynamic disks provide access to advance configuration features.
Windows Server 2008 allows you to configure various types of storage including RAID-0, RAID-1, and RAID-5 storage arrays.
A volume describes a logical unit of space that is made up of space contained on one or more physical disks.
A simple volume is type of volume consists of free space contained on a single physical disk. You can configure all of the available space on a disk as a simple volume, or you can configure multiple simple volumes using the space on a single disk.
A spanned volume is made up of free space from multiple physical disks. For example, if you have two physical disks in a server that are each 500GB in size, you can combine them into a single spanned volume that is 1TB in size.
A striped volume is similar to a spanned volume in that it is made up of free space from multiple disks and uses RAID-0 striping to interleave data across the disks, thus improving the read performance of the volume.
A mirrored volume is a fault tolerant volume consisting of two physical disks, in which the data on one disk is copied exactly on to the second disk.
A RAID-5 volume is also a fault tolerant volume where data in interleaved across three or more disks much in the same way as a stripe volume, but with additional information know as parity. If on disk in RAID-5 fails, the data on the failed disk can be rebuilt using the parity information stored on the other disks in the rest of the volume. A max of 32 disks can be used in this type volume.
When creating a new partition you can either assign the patrician a drive letter, or else you can configure a mount point that will appear as a folder within the existing drive letter.
Before you can manage a disk drive in Windows 2008 Server the disk needs to be initialized. With either of the two following styles:
MBR (Master Boot Record) – this partition style is recognized by down level operating systems.
GPT (GUID Partition Table ) – this partition style is recommended for disks larger than 2TB, or disks that are used in Itanium computers.
Installing Server Core:
The server core is introduced as a new option in 2008 for installing only the services required for a specific function/role (DHCP, DNS, file Server or domain controller) and takes up an extremely small footprint. The installation process for Server Core is identical to the installation of a full version of Windows Server 2008. Once a Server Core computer is installed, however, it can be managed locally using only command-line utilities and the limited GUI facilities installed on a Server Core computer. A Server Core computer will allow you to launch the Windows Registry Editor, Notepad, and a number of Control Panel applets. However, it does not include a Start menu and does not allow you to install or run any of the MMC consoles, such as Computer Management or Active Directory Users and Computer.
Installing and Initial Server Configuration:
Best practices when installing Windows Server 2008 recommends installing the software onto which type of media fresh (media that has never been used before) or previously used media(media containing existing files). If Windows Server 2008 is installed onto a disk partition containing a previous version of Windows, the files will be preserved but the software will not be usable. Note: The Windows Server 2008 distribution media contains a bootable system that can be used for a standalone software installation or to repair an existing installation.
Once you have installed Windows 2008 Server the software will automatically launch the ICT Initial Configuration Tasks. You should go through all of these tasks (Administrator password, time zone, windows update, networks settings, adding server roles and features …). Note: By default, the Windows Firewall is turned on. It is also especial important to download and apply any that have been released since the creation of the media you are using to install.
When setting up your network connection keep in mind a server usually has a static IP address so you will also need to manually setup the DNS address information.
Network discovery finds and accesses other computer and resources shared on the network. Warning if you inappropriately allow network discovery in a public network such as at a wireless café, you would be allowing anyone to access file shares on your system.
Configuring Server Roles:
To improve security and manageability of Windows 2008 Servers you use the Server Manager console to install one or multiple server roles. To reduce the attach surface on Windows 2008 computers, system files(executables and DLL files) associated with a particular role will not be installed on a server until not be install until the role is installed, instead of leaving unused software lying dormant on the server as a potential target for a network virus or worm. This also keeps the system/server cleaner to run these applications.
Configuring Server Storage:
Windows Server 2008 (and all Microsoft operating systems going back to Windows 2000) supports which two types of hard disks, basic and dynamic.
Basic disks use partition tables that are recognized and supported by older operating systems. All disks in a windows 2008 server start out as basic until they are converted to dynamic disks.
Dynamic disks provide access to advance configuration features.
Windows Server 2008 allows you to configure various types of storage including RAID-0, RAID-1, and RAID-5 storage arrays.
A volume describes a logical unit of space that is made up of space contained on one or more physical disks.
A simple volume is type of volume consists of free space contained on a single physical disk. You can configure all of the available space on a disk as a simple volume, or you can configure multiple simple volumes using the space on a single disk.
A spanned volume is made up of free space from multiple physical disks. For example, if you have two physical disks in a server that are each 500GB in size, you can combine them into a single spanned volume that is 1TB in size.
A striped volume is similar to a spanned volume in that it is made up of free space from multiple disks and uses RAID-0 striping to interleave data across the disks, thus improving the read performance of the volume.
A mirrored volume is a fault tolerant volume consisting of two physical disks, in which the data on one disk is copied exactly on to the second disk.
A RAID-5 volume is also a fault tolerant volume where data in interleaved across three or more disks much in the same way as a stripe volume, but with additional information know as parity. If on disk in RAID-5 fails, the data on the failed disk can be rebuilt using the parity information stored on the other disks in the rest of the volume. A max of 32 disks can be used in this type volume.
When creating a new partition you can either assign the patrician a drive letter, or else you can configure a mount point that will appear as a folder within the existing drive letter.
Before you can manage a disk drive in Windows 2008 Server the disk needs to be initialized. With either of the two following styles:
MBR (Master Boot Record) – this partition style is recognized by down level operating systems.
GPT (GUID Partition Table ) – this partition style is recommended for disks larger than 2TB, or disks that are used in Itanium computers.
Installing Server Core:
The server core is introduced as a new option in 2008 for installing only the services required for a specific function/role (DHCP, DNS, file Server or domain controller) and takes up an extremely small footprint. The installation process for Server Core is identical to the installation of a full version of Windows Server 2008. Once a Server Core computer is installed, however, it can be managed locally using only command-line utilities and the limited GUI facilities installed on a Server Core computer. A Server Core computer will allow you to launch the Windows Registry Editor, Notepad, and a number of Control Panel applets. However, it does not include a Start menu and does not allow you to install or run any of the MMC consoles, such as Computer Management or Active Directory Users and Computer.
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