This service is used to configure diskless clients in an RPC environment. Diskless workstations are desktop machines that do not have their own hard-disks. They must therefore boot from a centralized server. Their are numerous protocols that are used in such situations, including BOOTP, TFTP, RARP, and RPL.
In the Sun RPC environment, a diskless workstation may be able to boot directly from NFS. In order to log onto an NFS server, it must first discover the configuration of the server. In particular, it needs:
- Its own name, as assigned by the server.
- The domain it belongs into, which will determine which users can log onto the workstation.
- The location of the boot files on the NFS server, as well as directories for swap and data files.
In order to setup a boot server, the administrator will have to do normal NFS and NIS/YP configuration. The administrator will further have to place per-workstation configuration into a file called /etc/bootparams.
One of the first steps when booting is to send a WHOAMI query from the workstation to the bootparam server. The server sends back the client's device name as well as domain.
However, bootparam is not authenticated. This means that anybody can send a request to a server asking for the device/domain name of any other machine. "Cracking" this domain name is one of the first steps when breaking into an NIS environment.
