subnet-specific class

David W. Hankins David_Hankins at
Thu Apr 12 18:04:58 UTC 2007

On Thu, Apr 12, 2007 at 12:33:49PM -0400, Chuck Anderson wrote:
> match if subnet = 130.215.v.0/

class "nortel" {
  match if substring(option vendor-class-identifier, 0, 14)
				= "Nortel-i2004-A";
  vendor-option-space Nortel;

option Nortel.i2004-server-info "global value";

group {
  option Nortel.i2004-server-info "group specific value";

  shared-network {
    option Nortel.i2004-server-info "shared broadcast domain specific value";

    group {
      option Nortel.i2004-server-info "yet another group specific value";

      subnet 130.215.a.0 netmask {
	option Nortel.i2004-server-info "subnet specific value";
	pool {
	  option Nortel.i2004-server-info "pool specific value";

I should change the vendor-option-space example in the manpages.  It's
misleading to show that the config value 'should' be specified in the
same scope as the vendor space selection.

> Another approach would be to support subnet-specific classes with the 
> class defined inside the subnet block.

I don't think this is a good reason to replicate the existing option
cache mechanisms to find configuration caches that are relevant to
the client's context.

But there are possibly other reasons for this sort of thing,
particularly when dealing with billing classes.

ISC Training!  training at
Washington DC area, April 16-20 2007.  DNS & BIND, DDNS & DHCP.
David W. Hankins	"If you don't do it right the first time,
Software Engineer		you'll just have to do it again."
Internet Systems Consortium, Inc.	-- Jack T. Hankins

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