BOOTP/DHCP support

[Jens Rühmkorf]

Hello folks,

just some comments for BOOTP/DHCP support that might help:

> I tested DHCP a little bit for fai. Here are my comments.
> 
> 1. fai can use bootpc to get the information from a DHCP daemon.
> 2. If to much data is defined in dhcpd.conf, mostly the extra
>    options (option-17*) are lost.

dhcpd has a predefined priority list which options are more important than
others, the priority of some important options can be changed lateron. But
the extra vendor-tags will always be the last to be passed. 

> Now, which program causes the error ? bootpc has to problems getting 
> more data from a BOOTP daemon. In /etc/bootptab you can increase the 
> size using tag ms for larger data files. This is an option for the BOOTP
> server. DHCP also has an something similar
>                                  
> send dhcp-max-message-size 2048;  

This is the same option we use for nais (but on the client side, as you
mentioned below). If you want fai to work with bootpc you have to redefine
the default using 

option dhcp-max-message-size 1024; 

in your dhcpd.conf on the server side.

> [...]
> but it must be defined for the client. So, next thing is, I will look 
> if dhclient works with both bootp and dhcp server. Or has anyone a 
> trick to let bootpc and dhcpd talk to eachother correctly ? 

Imho, I think dhclient is the better approach since bootpc is not cleanly
implemented (not in terms of coding but of rfc-conformity). The only legal
way to increase the information you may retrieve more information using the
BOOTP-protocol (instead of DHCP) is using extension files. The author of
bootpc didn't think extension files were important enough (well for most
cases this is true ;). 

So, it IS possible to make dhcpd work with bootpc using "option
dhcp-max-message-size 1024;", BUT: Whenever you use any netbooting method
that depends on BOOTP (instead of DCHP or any other successor) there will be
problems because of the lack of rfc-conformity. In fact, you CANNOT use
netboot or etherboot when using the "ms" tag in bootptab or the option
"dhcp-max-message-size" in dhcpd.conf (netboot supports extension-files,
though). 

> P.S: The public cvs repository is nearly ready for use.

Well that let's me point out that there is anonymous read access available
for nais as well: 

password="anonymous", 
CVSROOT=":pserver:anonymous at vermeer.informatik.uni-koeln.de:/home/nais/CVS".

Keep in mind, that this is our experimantel tree with all kernel images and
such (about 7 MB size). 

Best regards and good luck working on DHCP,

Jens

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             network-based automatic installation system                   
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