Need vendor class identifier advice

Doug Barton dougb at
Wed Sep 18 06:52:20 UTC 2013

On 09/17/2013 10:30 PM, Peter Rathlev wrote:
> On Fri, 2013-09-13 at 14:13 -0700, Doug Barton wrote:
>> I could create 2 match classes and put 'deny class members of' options
>> in for both of them, but that seems inefficient. :)  I'm trying to write
>> a custom boolean match like this:
>> match if substring (option vendor-class-identifier,0,28) = "Cisco
>> Systems, Inc. IP Phone" or substring (option
>> vendor-class-identifier,0,14) = "Cisco IP Phone";
> Looks right as Keith points out.

Nice to know I haven't totally lost my touch. :)

> Regexp matching is expensive though. The most efficient way is probably
> the two-class (with subclassing) approach with two allow statements.

Actually they are deny statements ... I'm wondering if that affects the 
calculations regarding efficiency? Every non-phone client will be 
passing through the deny classes for every non-phone subnet (the vast 
majority of both).


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