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 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
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