On 31/01/14 16:25, Linux Luser wrote:
dhcp-ignore-names is concerned about the hostname, correct? I am
interested in the client identifier option sent in the DHCPREQUEST.
Ignoring this field would break RCF2131 (and probably some people's
networks!) but in my particular case, it may spare me some problems.
I understand, I'm proposing a new option, dhcp-ignore-clid, analogous to
the existing dhcp-ignore-names.
Maybe if I could selectively revoke leases, that would work. Could I do
this? I'm sure that dnsmasq keeps an internal cache, so that would have
to be flushed for a particular lease.
There is a utility in contrib/wrt in the source distribution, and a
binary in the Debiann package of dnsmasq, for releasing a specific lease
from the command-line.
On Jan 30, 2014 2:08 AM, Simon Kelley si...@thekelleys.org.uk
mailto:si...@thekelleys.org.uk wrote:
On 29/01/14 18:04, Linux Luser wrote:
We have a pretty tightly-controlled private network environment
which
we've configured to have a 1-to-1-to-1 relationship between
client MAC
address, hostnames and IP addresses. Apart from guest IP
ranges, we
have control over when clients get added to the network. Thus,
we can
detect duplicate MAC addresses before it becomes an issue.
In this setup, we can't need or want to use the client identifier
option of DHCP. In fact, it becomes a problem when we start doing
PXELinux installs, where a different client id gets sets during
a remote
install session, then when the install is complete and the new
OS boots
up, it gets a different IP address (because dnsmasq still knows
about
the lease it gave that same machine only 10 minutes ago!).
To get rid of this issue, we now supply a dhcp-host option to
dnsmasq
each time we want to do a remote reinstall. The option looks
something
like this:
dhcp-host=MAC addr,id:*,hostname,IP addr,set:install
This works, since the id:* part tells dnsmasq to ignore the
client ID
in favor of the MAC address. But now to my question. Can this be
done
for ALL DHCP requests? Is there a global identify-by-mac-only
option?
If not, would you be willing to entertain the idea. I know many
others
have done this for some time now, using other DHCP server
software, so I
know it's possible and there doesn't seem to be any ill effects
of this.#
There isn't a global option to do this, but there is precedent, in
the form of --dhcp-ignore-names for adding it, and actually that's
something more useful, since the tag system allows the setting to be
applied to classes of clients (which could, of course, be all clients)
Maybe this is not a good idea? Like I said, we have a fairly
controlled
environment, so it would work for us. I could see how this would be
unnecessary for common setups, though. Or environments that have
many
VMs running on a single host and simply bridge their network
interface
may want to use the client identifier option so each VM gets a
unique
IP even if they're running on the same machine or t But it would
be nice to
have a greater level of control over this.
Thanks for your time. And GREAT piece of software, by the way.
dnsmasq
is a HUGE time saver and makes changing configurations
straight-forward.
Do you accept donations? :)
Donations by Paypal to si...@thekelleys.org.uk
mailto:si...@thekelleys.org.uk are always welcome, or you could
commission me to add new features. I'm available for that on a
consultancy basis, cheaper for stuff which goes back into the
dnsmasq GPL codebase, more expensive for proprietary code.
Cheers,
Simon.
--
daV.e
_
Dnsmasq-discuss mailing list
Dnsmasq-discuss@lists.__thekelleys.org.uk
mailto:Dnsmasq-discuss@lists.thekelleys.org.uk
http://lists.thekelleys.org.__uk/mailman/listinfo/dnsmasq-__discuss
http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
_
Dnsmasq-discuss mailing list
Dnsmasq-discuss@lists.__thekelleys.org.uk
mailto:Dnsmasq-discuss@lists.thekelleys.org.uk
http://lists.thekelleys.org.__uk/mailman/listinfo/dnsmasq-__discuss
http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
___
Dnsmasq-discuss mailing list
Dnsmasq-discuss@lists.thekelleys.org.uk
http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
