[syslinux] Network Boot IP Configuration Dilemma

H. Peter Anvin hpa at zytor.com
Fri Sep 5 17:33:21 PDT 2003


Fred Feirtag wrote:
> 
> If the pxelinux.cfg "IPAPPEND 1" entry is used, an "ip=..." string is
> appended to the parameters passed to the kernel.  This is, as I will
> ultimately conclude below, a less problematic approach, however,
> it is in need of being extended to use the currently unused "device"
> parameter.
> 

Except, it's not.  If the "device" parameter is specified then the
kernel may very well configure a different device.  Always tagging
::eth0: at the end is highly problematic (in fact, it's downright wrong.)

There is another issue to keep in mind: unless you're running a dhcp
server in userspace, your dhcp lease will eventually time out and the
dhcp server may assign an IP address conflict.

> 3)  A second DHCP server answers the request differently than
>    the first.  This is from my experience, the much more likely
>    and frequent problem.  Where different servers, possibly
>    unintentionally, are answering on the same network, one may
>    often answer first for the first request, and the other may
>    often answer first for subsequent requests, as the busier, but
>    faster system has dhcpd swapped in.

Of all your problem descriptions, this is the only one which isn't
actually a problem.  You will either obtain a legal configuration, or
you have a much more serious problem of two unsynchronized dhcp servers
stomping on each other.

Since both your #1 and #2 are problems that would occur *with* your
change, and #3 is not a problem in a properly set up environment, I
don't see this as beneficial in any form.  I am, however, willing to
listen to arguments to the contrary.

	-hpa




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