Beware: change in configuration file semantics
David W. Hankins
David_Hankins at isc.org
Wed Feb 13 16:38:01 UTC 2008
On Wed, Feb 13, 2008 at 12:42:14PM +0000, Niall O'Reilly wrote:
> Prior to ISC DHCP v3.1.0, it was possible to declare an option (for
> example):
>
> option tftp-server-address code 150 = ip-address;
>
> and subsequently to refer to that option as follows.
>
> host ... {
> ...
> option tftp-server-address server.example.net;
> }
so far as i am aware, this is true of all present and future releases
of ISC DHCP.
> /etc/dhcpd.conf line 53275: unknown option dhcp.tftp-server-address
> option tftp-server-address server.
i am unable to replicate this (using dhcpd -t) with any of the
versions 4.1.0a1, 4.0.1b1-HEAD, 4.0.0, 3.1.1b1-HEAD, or 3.1.0, some of
which have yet to be released. none complain.
> Was this change intended?
> If so, is it documented somewhere?
> Is the work-around I suggest likely to be safe?
i have a suspicion that you have found a typo in one of your config
files, or an extremely odd bug.
note that it has always been the case that an option foo declared
thus:
option foo code bar = baz;
is implicitly a member of the DHCPv4 root options space - a DHCPv4
option code and format definition. this means that the server has
always:
1) substituded dhcp.foo where 'option foo' lacks a dot.
2) installed into the 'dhcp option space' the option declaration for
any 'foo' which lacks a dot.
so this is not new in any sense of the word between any current and
previous software version - the server has always assumed dhcp. when
it has been omitted, and the statements 'option tftp-server address'
and 'option dhcp.tftp-server-address' are completely equivalent. i
don't know if the author intended this to save typing or to sound less
redundant (dhcp.dhcp-...) or what.
--
Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
Why settle for the lesser evil? https://secure.isc.org/store/t-shirt/
--
David W. Hankins "If you don't do it right the first time,
Software Engineer you'll just have to do it again."
Internet Systems Consortium, Inc. -- Jack T. Hankins
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