On 09.01.19 08:14, john doe wrote:
On 1/8/2019 11:31 AM, smicha wrote:
Hi John,
thanks for your reply.
I did some tests with your hints.
On 7.1.2019 17:41, john doe wrote:
Some hints from dnsmasq.conf:
# Give the machine which says its name is "bert" IP address
# 192.168.0.70 and an infinite lease
#dhcp-host=bert,192.168.0.70,infinite
Do not work with my setup, because when we re-deploy a VM, the MAC
address will be autom. changed.
The re-delpoyed VM will than get a different IP as the old vm had before.
I just tested this option and the behavior described is correct with
dnsmasq 2.76, from the man page:
I have running the version 2.78.
"--dhcp-host=lap,192.168.0.199 tells dnsmasq to always allocate the
machine lap the IP address 192.168.0.199.
Addresses allocated like this are not constrained to be in the range
given by the --dhcp-range option, but they must be in the same subnet as
some valid dhcp-range. For subnets which don't need"
Yes, the config "--dhcp-host=lap,192.168.0.199" is working. The VM with
the hostname "lap" will get the IP 192.168.0.199.
But, I have the problem, when I have a new VM, a new version of the VM
"lap" which have a different MAC address.
Than, that new version of VM "lap" get not the 192.168.0.199. They get
an other IP from the pool.
As long as a client use the hostname ("lap") the same IP will always be
given to that client, the MAC address is not used.
As far as I see, for the "first" IP provisioning that is true -> the
Hostname is enough.
But, than the "dnsmasq.leases" file have also the MAC address and
Client-ID values stored, which will be compared an the next DHCP Requests.
If than one of the values are different (MAC, CLIENT-ID) the DHCP-Client
will get an other IP.
Please see below, a example...
See also (1) for more info on 'dhcp-host'.
1) http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html
Maybe is it possible to "patch" the code of dnsmasq, where dnsmasq can
ignore the MAC address in the DHCP task?
Possibly, more nolageable dnsmasqer would need to chime in to do that
though! :)
If '--dhcp-host=hostname,IP' is not working for you more info would need
to be provided.
BTW: the VM "lap" does not have set a special "DHCP-Client-Identifier",
so it use for DHCP-Client-ID the MAC address.
Here some outputs of the dnsmasq.leases file:
# inital DHCP-Request:
1547107342 00:50:56:85:02:fa 192.168.0.199 lap 01:00:50:56:85:02:fa
As you can see, the VM "lap" (MAC 00:50:56:85:02:fa) get the expected IP
-> so far so good.
Next, I power off the VM "lap" without a DHCP-Release and deploy a copy
of the VM "lap" which have than an other MAC (00:50:56:85:02:ff) ! ->
the MAC will always set by the deployment of a new VM version.
Now, I start the new version of the VM "lap" (the old version of the VM
"lap" is no longer available.
The dnsmasq.leases looks now, like this:
1547116110 00:50:56:85:02:ff 192.168.0.200 lap 01:00:50:56:85:02:ff
1547107342 00:50:56:85:02:fa 192.168.0.199 * 01:00:50:56:85:02:fa
As you see, the VM "lap" have now the IP "192.168.0.200" and not the
expected IP "192.168.0.199.
Do you have an idea how I can fix that?
I tested different options with "--dhcp-host", but with no luck.
I hope you can help my.
May do you have an hint in which part of the code, I can fake the
incoming/received "DHCP CLIENT-ID". I think that is one of the key's to
fix the problem.
As I said before in a prev. mail. The problem is not there, when the
DHCP-Client sending a uniq DHCP-Client-ID. In Linux that is not the
problem i can set that, but in Windows I do not have the option to set
the DHCP-Client-ID ! :-(
Many thanks
Michael
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