DHCP + ldap

Richard Pijnenburg richard at softwaredev.nl
Tue May 11 19:30:15 UTC 2010

On Tue, 11 May 2010 12:17:31 -0700, "David W. Hankins" <dhankins at isc.org>
> On Tue, May 11, 2010 at 09:33:48AM +0200, Richard Pijnenburg wrote:
>> I've been doing some more work with it.
>> I can define the hosts on the fly, but the subnets need to be specified
>> before starting the dhcp server.
>> Adding a subnet to the shared network while the dhcp server is running
>> won't see it.
>> I hoped this could be different, or is it not possible due to the
>> of dhcpd?
> My understanding of the LDAP patch (this should be true of the manual
> patch as well as what we committed to 4.2.0b1) is that it does not
> query the LDAP database during runtime, as that would be very difficult
> with the particular way the DHCP server is architected currently, but
> rather uses the LDAP database to build a dhcpd config at startup.
> More or less LDAP is being used as an "include."  Literally, actually,
> the LDAP related sources in dhcpd produce text to pass into the config
> parser at startup.
> So the configuration has to be in the LDAP database at the time the
> server starts, and after making changes to LDAP the server must be
> restarted.  So far as I'm aware, this applies to host records as
> well as subnets.
> Would this explain the disparity in function you were seeing between
> the 4.2.0b1 and 4.1.1+patch server you tested?  When you started the
> 4.1.1 server that constituted a restart?

Hi David,

I've restarted the 4.2.0b1 version multiple times.
Just as a test i've removed my host definitions, started the dhcp server.
Started the client and didn't get an IP.
Added the host definition and i got an IP.

Seems that the subnet defs are loaded when starting the dhcp server.
The hosts are looked up dynamic.
This can also be set to static, but seems it only counts for host defs.

in the 4.2.0b1 version the error is that it finds the details to send, but
doesn't send them to the client.
With the same ldap database i went to 4.1.1 and worked instantly.
Also the logging to the file doesn't work + 2 rules are giving compile
errors when the DEBUG option is enabled.

Best regards,


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