DHCP with LDAP config should load class definitions first

Binary package hint: dhcp3-server-ldap

Take as example the following dhcpd.conf (just as example, it's syntax is not right):

global parameters...

class "VoIP_Phones" {
   match if (substring (hardware,1,3)=00:04:13);
}

class "Other_Clients" {
   match if not (substring (hardware,1,3)=00:04:13);
}

subnet 204.254.239.0 netmask 255.255.255.224 {
   subnet-specific parameters...

   pool "VoIP" {
      allow members of "VoIP_Phones";
      deny members of "Other_Clients";

      pool-specific parameters...
   }

   pool "VoIP" {
      deny members of "VoIP_Phones";
      allow members of "Other_Clients";

      pool-specific parameters...
   }
}

If you want to have such kind of configuration LDAP based, you would create corresponding LDIF files and load them in the LDAP.

But - and that's tricky - you need to ensure to load all classes that get referenced by the pool declarations later get loaded into the LDAP before the pool declarations.

In other words - DHCP does not automatically load class declarations first. If you you first save the pools into LDAP, followed by the classes, DHCP will throw an error on restart because it finds the reference to the class before the class declaration itself.