CNR DHCP Client-class

dave.joyce · ‎01-09-2008

We are using CNR with multiple scopes to provide ip addressing for both computers and IPTV set top boxes. The STB's require boot params in dhcp option-131 and option-240. I have set up a client-class-policy that contains the two options and when I set up a client with an exact mac address, then the information is provided correctly.

The problem is we have hundreds of STB's. How do I get CNR to generalize the client mac address to just the first 3 bytes?

I have tried creating a client with 00:00:00 for the last three bytes and then altering the dhcp-client-identifier to match, but it doesn't work.

The docs state that you can create a client-lookup-id expression but shows no examples.

Thanks.

owillins · ‎01-16-2008

use the following documents it contains decsription as well as examples for client-lookup-id expression

http://www.cisco.com/en/US/docs/net_mgmt/network_registrar/7.0/user/guide/UG25_Exp.html

dave.joyce · ‎01-16-2008

Reread the docs closer and found that the environment parameter 'default-client-class-name' is only visible in the pre-client-lookup extension. So in the post-packet-decode extension I check the request parameter 'dhcp-class-identifier' and then set a environment parameter stb-type to a class name.

In the pre-client-lookup I check to see if the stb-type is in the environment dictionary. If it is then I set 'default-client-class-name' to that value. This forces the DHCP to use the client-class of the same name as the default for this DHCP request. Since I set the option 131 in the appropriate client-class-policy then it all works. Don't even need a client set up at all.

Thanks for the response on expressions. Looks like I may have been able to do it that way too.

upule · ‎06-03-2008

create a client class (not a client)

evaluate the dhcp-client-identifier and assign the client class.