This time around we’ll begin a three-part series on Remote Installation Services (RIS), a component introduced with Windows 2000 as part of the Intellimirror technologies designed to reduce total cost of ownership (TCO) and make IT professionals’ work lives a little easier.
How RIS Functions
RIS works by creating a preboot execution environment (PXE) that enables a compliant client PC to gain basic TCP/IP network connectivity. PXE (pronounced "pixie") technology is not integrated into every network card, so you must ensure that you have a PXE compliant adapter before you can use RIS. The client requirements for RIS are listed in the next section.
Once network connectivity is established, a series of scripts can be run to bring the client to the point of installing the operating system. For NT 4.0 administrators, this ability makes RIS a "must have." In the past, it has often been a frustrating experience trying to reinstall an operating system on a computer when you didn't have a boot floppy or installation CD handy. You knew all of the software you needed was on the network, and the computer you were trying to reinstall had a network card, but you couldn't get network connectivity established. RIS ends that frustration, because network connectivity is established at the hardware level through the interaction of the network card with the network.
With RIS, an administrator can choose to have a computer go through a CD-like installation of Windows 2000 Professional, as if a normal installation was taking place off of a CD. Alternatively, an administrator could customize the installation and to the point of scripting it with an answer file so that the user would not be required to choose any options during setup.
Now that we have a basic understanding of RIS in terms of what it does, let's discuss the components required for RIS.
RIS Requirements
RIS depends on a number of components already being installed and configured on a Windows 2000 network in order to function. They are:
* Remote Installation Services
* Domain Name Server (DNS)
* Dynamic Host Configuration Protocol (DHCP) Server
* Active Directory
In the next sections, we will discuss each of these Windows 2000 components as they relate to using RIS.
Remote Installation Services
Windows 2000 includes Remote Installation Services (RIS) as an optional component that can be installed through the Windows Components Wizard of the Add/Remove Programs applet in Control Panel. RIS runs as a service on at least one Windows 2000 Server system on the network, listening for client requests. In addition, the RIS server stores the operating system images that the client computer can choose from when they invoke RIS. An administrator can use Group Policy to determine what images should be available to what users.
Setting up a RIS server will be discussed in Part 2 of this series.
Domain Name Server (DNS)
The domain name service (DNS) is the service that enables RIS clients to find RIS servers on the network. Windows 2000 RIS servers register themselves in DNS, so that when a RIS client establishes network connectivity it has the name and IP address of a RIS server to pull an image from. Microsoft DNS is not required as long as the third party DNS server used supports RFCs 2052 (SRV RR) and 2136 (dynamic updates).
Dynamic Host Configuration Protocol (DHCP) Server
In order to establish network connectivity, a RIS client must have an IP address. Since the process all takes place at the hardware level, there is nowhere to assign a static IP address. RIS therefore uses dynamic addressing in order to obtain an IP address and connect to the network. For a RIS client to obtain a dynamic address, there must be a DHCP server running on the network. This can either be a Microsoft DHCP server or a third party DHCP server.
Active Directory
RIS is dependent on Active Directory in order to function. The reason being is two-fold. First, RIS uses Group Policy, which is dependent on Active Directory, in order to determine permissions for user accounts and computers accounts prior to supplying RIS image choices to the user. Secondly, RIS uses network configuration settings stored in Active Directory to determine information such as what RIS server should be used in the case where multiple RIS servers exist on a network. In addition, Active Directory information is used for things such as using a standard naming convention for new computers and determining what domain or OU to place the new computer in.
With an understanding of the dependencies RIS has, let's look at the server and client components that make up RIS.
RIS Client and Server Components
In addition to the dependencies that RIS has that were listed above, there are components at both the client and server that enable RIS to function. In this section, we will discuss the client and server components of RIS.
Client Requirements of RIS
There are a number of requirements a client computer can meet in order to use RIS. These requirements are:
* Computer must meet NetPC or PC98 standards
* Computer must have a compatible network adapter
* Computer must have a compliant BIOS
NetPC or PC98 Standards
One way a computer can meet the requirements of RIS is to conform to the NetPC or PC98 standard. A client computer that meets the requirements set forth by either the NetPC or PC98 standard will include PXE functionality. Compliant computers must have version 1.0b at minimum to work with RIS.
There are additional standards within the NetPC and PC98 standards, but for the purpose of this book only PXE and Plug and Play requirements are discussed.
Compliant BIOS
Another way a PC can meet the requirements of RIS is to have a compliant motherboard BIOS, which will include the necessary PXE functionality for RIS. If you don't currently have a PXE capable motherboard, see the manufacturer about a possible flash upgrade since almost all motherboards are now upgradeable.
Compatible Network Adapters
Additionally, a compliant client computer can simply have a compatible network adapter installed in order to use RIS. A compliant network adapter will be PXE compliant, meaning it supports the preboot execution environment standard. Due to Plug and Play requirements, a compliant network card will also be PCI-based. This excludes PCMCIA network adapters typically found in laptops, so if you want to use RIS with a laptop system you must first connect the laptop to a docking station that contains a PCI network adapter that also has PXE functionality.
If the motherboard is not compliant and the computer does not meet NetPC or PC98 standards, and you don't have a PXE complaint network adapter, it might still be possible to still use RIS. Windows 2000 includes a utility, RBFG.EXE, that allows an administrator to create a bootable floppy disk that emulates the PXE environment.
Hardware Requirements
In order to use RIS on a client computer, the client must meet the following hardware requirements:
* Pentium 166 or faster CPU
* 32MB of RAM minimum (64MB recommended)
* 800MB or larger hard drive
* DHCP PXE-based boot ROM or network adapter supported by the RIS boot floppy
Client Installation Wizard
The Client Installation Wizard is the client-side piece for RIS, which is downloaded to the client and communicates with the RIS server. A default set of screens is presented to the user, which are provided by the Boot Information Negotiation Layer (BINL) server-side service. These screens guide the user through the Client Installation Wizard to logon and select Windows 2000 Professional installation options that have been defined by the administrator. The user invokes the Client Installation Wizard by pressing F12 once the PC's POST process has completed and before the operating system starts booting.
It is important to note that the boot process is not secure, information is sent over the network in clear text that can be read with a packet sniffer. Therefore, you should ensure that there are only limited RIS servers on the network and control over who is allowed to setup and configure RIS servers in general.
Now, let's look at the server components for RIS
Server Components of RIS
The RIS services on a server are less dependent on specific hardware than client computers, though there are some hardware requirements of which to make note. These requirements are:
* Pentium 166 or fast CPU (200+ recommended)
* 96-128MB of RAM required when running Active Directory, DNS, and DHCP services
* 10MB Ethernet adapter (100MB recommended)
* Access to Windows 2000 Professional installation files (can be CDROM or network share or local directory with a copy of the files)
* 2GB hard disk for the RIS servers folder tree. It is recommended to devote an entire hard disk partition to the directory tree for RIS.
* NTFS formatted partition for RIS images (RIS cannot be installed on Distributed File System (Dfs) or Encrypting File System (EFS) volumes)
As we previously discussed, the requirements to use RIS from the server end include Active Directory, DNS, DHCP, and the Remote Installation Services service. When RIS is installed through Add/Remove Programs (RISetup.exe is the program that actually installs RIS, and is discussed later), there are additional services installed on the server. These services include:
* Boot Information Negotiation Layer (BINL) -- As discussed previously, this is the service that listens for client DHCP/PXE requests. Additionally, BINL redirects clients to the appropriate files needed for installation during the Client Installation Wizard. Lastly, it is the BINL service that verifies logon credentials with Active Directory.
* Trivial File Transfer Protocol Daemon (TFTPD) -- RIS uses TFTP to initially download all files to a client that are necessary to begin the Windows 2000 Professional installation. Included in this download is Startrom.com, which is the bootstrap program that displays the message for the user to press F12 for Network Service. If the user does press F12 within three seconds, the Client Installation Wizard is downloaded through TFTP to the client computer.
* Single Instance Store (SIS) -- The SIS service seeks to reduce disk space requirements for RIS images by combining duplicate files. The service contains an NTFS file system filter (RIS, as you will recall, can only be installed on an NTFS partition) and the service that manages images on the RIS installation partition.
There is another server component, RIPrep.exe, that is used to create RIS images. Creating RIS images is discussed later in part 3.
Now that we have discussed the basics of RIS, in part 2 we’ll get our hands dirty with a RIS installation!
Questions or Comments? Will
can be reached at WWillis@Transcender.com