bootptab's intrinsic tags and vendor tags

[Mike Hammer <mike-hammer@usa.net>]

Hi,

I'm trying to understand all these "tags" used in bootptab.

Can the client send a bootp request that 	includes what the vendor 
options it wants in the bootp reply packet?  According to RFC951,
bootp client is supposed to send only a bootp request packet with
IP set to 0.0.0.0 and it's MAC address.

I'm just getting into using vendor extension tags with Etherboot
and Netboot to experiment with menus, different boot image selection,
password, commandline, etc.  I'm sort of starting out with sample
bootptab file that has bunch of "Tn" entries.

I guess the recommended way for the vendor extension information
to be transferred is to have client get the bootextension-file name
in the bootp reply packet and have it TFTP'ed from the server.
I initially tried to send all the tags in reply but it seems there's only 
room for 64 octes of payload space in bootp reply packet for these vendor 
extension tag data.

However i'm having little difficulty using "bootpef" utility.  Is this 
program supposed to generate a binary or text file from bootptab?
I use "bootpef -c /tftpboot" and the output file is only like 5 Bytes
and looks like a binary file.  Just what is included in this 
bootextension-file?

Also someone mentioned about being careful with bootextension-file when 
sharing it with multiple clients and using "chroot".  I would think
that there's no problem in sharing a single bootextension-file across
multiple clients since i would think bootextension-file contains just
a menu creation information.  

Can someone give little detailed insight into "bootpef" usage of
"-c" option?  I think this is tied to "chroot" usage of tftpd.  Why
does "bootpef" care about current directory when creating the
bootextension-file?  I thought that extension filename is supposed
to be specified in bootptab as "ef" tag which gets sent in the bootp
reply packet and if so, the client should know that the extension file
is located in directory specified in "td" tag.

This is getting all little too confusing.  :-(

Thanks in advance,

PS. I've read the manpage on bootptab and combed the internet.  Can
    someone point to a good reference to bootp tags other than RFC's?
    If i'm going to be developing my own tftpd and bootpd, are the
    RFC's the only source of information?

hammer