[Udpcast] Another DHCP config question

[Donald Teed]

On Wed, 3 Nov 2004, Jaco Kroon wrote:

> If you find any really good documentation on DHCP, let me know.

Yes, I find that getting good documentation on the oldest
Internet stuff - mainly the ones from ISC - is difficult.
There is no O'Reilly book, which is surprising.
The existing docs (man pages for dhcp, dhcpd.conf, and dhcp-options)
cover the granular information, but other than finding existing
examples, it is hard to see the DHCP stuff documented in a wholistic way.

For example, nothing I found indicated that class labels had to
be unique, even though they appear in different subnet sections
of the config.  The examples at isolinux do not mention
a class with match.

> I note you are using pxelinux.  pxelinux already has this functionality built 
> in, thus no need to /pxe1/pxelinux.0 and /pxe2/pxelinux.0, if I recall you 
> have a config directory with default in it to provide a default config, but 
> it tries different names first, starting the the complete ip address written 
> out in hex, for example C0A80101 for 192.168.1.1, and then it starts chopping 
> off digits at the end until it is left with the empty string (at which point 
> it loads default) untill it finds a config.  Just read the docs again to make 
> sure I'm not talking bollocks here.

I knew I could mention the full hexed IP, but I didn't realize how
a partial match could be done.  We have over 5000 clients, so
just breaking it down to subnets getting custom boot menus is all we need.

One of the possible services we may put out is a self-serve udpcast
session, so this thread is a relevant topic to the list.

Thanks for your suggestion on making hex IP default files.
I think this may prove to be the simplest solution.  At least
we can implement it without testing and causing disruptions
to the DHCP server.

--Donald Teed