NAME

ndbootd — Sun Network Disk (ND) Protocol server

SYNOPSIS

ndbootd

[-s boot2] [-i interface] [-w windowsize] [-d] boot1

DESCRIPTION

ndbootd is a server which supports the Sun Network Disk (ND) Protocol. This protocol was designed by Sun before they designed NFS. ND simply makes the raw blocks of a disk available to network clients. Contrast this with the true namespace and file abstractions that NFS provides.

The only reason you're likely to encounter ND nowadays is if you have an old Sun 2 machine, like the 2/120 or 2/50. The Sun 2 PROMs can only use ND to boot over the network. (Later, the Sun 3 PROMs would use RARP and TFTP to boot over the network.)

ndbootd is a very simple ND server that only supports client reads for booting. It exports a disk that the clients consider to be /dev/ndp0 (ND public unit zero). The disk is available only to clients that are listed in /etc/ethers and have valid hostnames. (Sun 2 PROMs don't do RARP, but they do learn their IP address from the first ND response they receive from the server.)

boot1 is a file containing the mandatory first-stage network boot program, typically /usr/mdec/bootyy. The layout of the exported disk is:

• block 0: normally a Sun disklabel (but ignored by the PROM)
• blocks 1-15: the first-stage network boot program

With the -s boot2 option, ndbootd will also make a second-stage network boot program available to clients, typically /usr/mdec/netboot. When boot2 is a filename, that file is the single second-stage network boot program to be served to all clients.

When boot2 is a directory name, typically /tftpboot, ndbootd finds a client's second-stage network boot program by turning its IP address into a filename in that directory, in the same manner later Sun 3 PROMs do when TFTPing (i.e., if a client has IP address 192.168.1.10, ndbootd expects to find /tftpboot/C0A8010A.SUN2 ).

When used in this last manner with an ND-aware first-stage boot program, ndbootd serves the same purpose in the Sun 2 netboot process as tftpd(8) serves in the Sun 3 netboot process.

Any second-stage network boot program always begins at block 16 of the exported disk, regardless of the length of the first-stage network boot program.

All first- and second-stage network boot programs must have all executable headers stripped off; they must be raw binary programs.

The remaining options are:

-i interface

Only listen for ND clients on interface interface. Normally ndbootd listens for clients on the first non-loopback IP interface that is up and running.

-w windowsize

This adjusts the window size of the ND protocol. This is the number of 1-kilobyte packets that can be transmitted before waiting for an acknowledgement. Defaults to 6.

-d

Run in debug mode. Debugging output goes to standard error and the server will not fork.

FILES

/etc/ethers

/etc/hosts

SEE ALSO

tftpd(8)

BUGS

Whether or not there is a second-stage network boot program, the exported disk appears to all clients to have infinite length. The content of all blocks not used by the first- or second-stage network boot programs is undefined. All client reads of undefined blocks are silently allowed by the server.