To add some filter rules in conf file

Jeff Haran jharan at Brocade.COM
Mon Oct 19 17:46:30 UTC 2009

From: dhcp-users-bounces at [mailto:dhcp-users-bounces at] On Behalf Of Ashmath Khan
Sent: Monday, October 19, 2009 1:48 AM
To: Users of ISC DHCP; dhcp-users at
Subject: Re: To add some filter rules in conf file

That's correct, I have the same understanding. But the issue is this:
I have a series of rules to be run in order, if a rule is met, then stop. It would be something like this:
rule1: match a string in vendor option, select a pool etc
rule2: match a different string in vendor option
rule3: if vendor option doesn't exist select a pool etc
rule4: see if client falls in the h/w address range, select a pool etc.
rule5: see if client has requested for so and so option
So, I can't put all denies in one pool, like you did below.

If dhcpd doesn't currently support this, I need to do code changes to move further. Can you or somebody suggest me, if you have already worked on making changes ? or is there any other separate list which has dhcpd developers(may not be the actual owners) ? or is there any other GPL based dhcpd for Linux ?


Just a thought that might work for you without code changes.

I would think that any set of sequentially applied rules like the above could be represented by an equivalent set of non-sequentially applied rules, at the cost of additional complexity in the non-sequential rules. For example, say your sequential rule set was:

rule 1: If its red, use the red pool, else
rule 2: If its fat, use the fat pool, else
rule 3: If its tall, use the tall pool, else
rule 4: Use the cold pool

This could be represented by an equivalent set of class statements that I believe would yield the same results without any dependency on the order of the rules' evaluation:

class red: If its red, use the red pool;
class fat: If its fat and its not red, use the fat pool;
class tall: If its tall and its not red and its not fat, use the tall pool;
class cold: If its not red and its not fat and its not tall, use the cold pool;

Jeff Haran

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