Remote Installation Services
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Remote Installation Services is a Microsoft-supplied server that provides Preboot eXecution Environment (PXE) BIOS enabled computers to remotely execute boot environment variables.
In short, a workstation can boot from a variety of methods - via floppy disk, local physical disk (or other media) or via the network. At boot time, a workstation that has been set to boot primarily from PXE will issue a BOOTP request via the network. BOOTP and DHCP are closely related - a workstation sends a request for a 2nd level TCP/IP unique identifier (IP address) based on the machine's MAC address, a unique number based on two parts - a manufacturer code and a unique number. The machine will also advertise it's GUID or UUID (Globally Unique Identifier / Universally Unique Identifier) if the machine has one. If the machine has a GUID, the machine will advertise its GUID / UUID over a MAC address.
Once received, a BOOTP server will not only supply the IP address to the machine, but enable booting from remote media. In this case, the Microsoft RIS server will issue a floppy disk boot image, which can then be used to fetch either a system image file, from a third party system such as Symantec Ghost or Acronis TrueImage.
Following execution, the system will configure itself based on this information and will allow the system to boot as if a floppy disk was inserted. Following the use of a third party imaging solution, it is necessary to either directly alter the registry to change the system's unique ID, the SID, or using the sysprep utility from Microsoft, the system will re-run the final configuration of an installation - which generates a unique SID and if required, will join a Windows domain.
On Windows 2003, two services are required to provide Remote Installation Services. These are DHCP and Remote Installation Service. The Remote Installation Service doubles as a proxy DHCP server to provide Boot Server and Filename instructions to clients. These however override any boot server options sent by the DHCP server itself. The Remote Installation Service utilises UDP port 4011[1], and provides to clients the content of each page OS Chooser displays. Additionally, this service provides drivers (such as for Network Interface Cards) to the clients. These are required to launch OS Chooser, and allow it to mount the share (REMINST) that the images are stored in.
It is possible to install or boot other Operating Systems through RIS, such as a GNU/Linux distribution through the Linux Terminal Server Project.
Remote Installation Services has been replaced with Windows Deployment Services in Windows Server 2003 Service Pack 2 and Windows Vista.
