No empty shared-network allowed version 4.2.4

Ryan Gray ryantgray at
Tue Oct 13 15:44:19 UTC 2015

Yes.  I just tested it myself, and it's happy with an empty subnet.  The
ocd monster in me is going to have to go back through the RELNOTES to see
if this is documented somewhere.  Either behavior is fine with me;  I was
just cranky about the fact that it changed.  The workflow in my application

- All DHCP information (settings, shared-networks, class/pool matching,
etc.) is in a mysql db.
- Web interface interacts with that db.
- Upon changes in the web interface, a php class (job) is fired off to
rewrite the dhcpd.conf based on what's in the db, and then it restarts the
dhcpd service.

The only change I had to make was to *not* fire the rewrite/restart job
when a shared-network is added.  Probably complete hackery, but it works.

I've been super intrigued to try Kea, but so far all I know about it is
"dhcp + mysql".  I'm a little reluctant to jump outside the box of
traditional isc dhcp because the people who will be using this interface
seem to really like the fact that if the web interface is broken (trust
issues!), they can still just hop on and configure things like they do
now.  All that said, if Kea is keeping leases in mysql, it would be
absolutely priceless to do away completely with caring about parsing
dhcpd.leases.....that, my friends, has been the bane of my existence over
the years.

Really appreciate your input here.  I haven't been a subscriber to this
list in longer than I care to remember, but it's good to be back.


Ryan Gray

On Tue, Oct 13, 2015 at 10:12 AM, Glenn Satchell <glenn.satchell at
> wrote:

> On Wed, October 14, 2015 1:29 am, Glenn Satchell wrote:
> > On Tue, October 13, 2015 10:00 pm, Simon Hobson wrote:
> >> Ryan Gray <ryantgray at> wrote:
> >>
> >>> I have a need for empty shared-network declarations in my dhcpd.conf
> >>> file.  Like so:
> >>>
> >>> shared-network VIDEO {
> >>> }
> >>
> >> Why ?
> >> If it's just a marker for something you may add later, make it into a
> >> comment.
> >
> > My guess is they "fixed" something in the parser. Can you put an empty
> > subnet declaration in it for a subnet you don't have, eg:
> >
> > shared-network VIDEO {
> >   subnet netmask {
> >   }
> > }
> This does parse correctly, but I just saw your other message, so this
> probably won't help.
> The RELNOTES file in the source release lists every change made, so you
> can go back looking for changes. Nothing obvious though.
> regards,
> -glenn
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