Max num of static entries

Frank Bulk - frnkblk at
Thu Aug 19 03:12:08 UTC 2010

Thanks, much appreciated.  We might consider using this approach in the future, too, and this approach should work equally for ONTs and DSL ports.


From: Marc Perea [mailto:marccp at] 
Sent: Wednesday, August 18, 2010 8:41 AM
To: dhcp-users at; Frank Bulk
Subject: RE: Max num of static entries


Hi Frank,

before v4.2.0 we were matching if agent.circuit-id existed and directly matched an ascii string that our access gear sent for a subscriber port, then we'd assgin an address from a specific pool with a range of 1 IP. It was clunky and painfully slow, but it worked and fit our requirements. That said, we were shopping around for a new DHCP server.


Then 4.2.0 came out and had a short snippet that said something like, -added the ability to match a host based on option information. I wondered what that meant and dug into some testing, and lo and behold, you can now match a host based on relay agent option 82 exactly like it was a host matched on mac address! It was revolutionary for us. Our homegrown provisioning system that was taking well over a minute per click (web form) is now down to just a few seconds (it talks to several servers). Prior to then it was waiting over a minute, in sequence (not multi-user friendly because of the single flat file) on DHCP to do provisioning because ISC can't handle config changes on the fly and requires a restart. That part hasn't changed, we still restart the service dozens, maybe hundreds of times per day, but it restarts now in under a second.


Anyways, the new syntax allows us to say, for example:


host 31052101 { host-identifier option agent.circuit-id ""; fixed-address x.y.z.q; } #7017050083

>>> Frank Bulk <fbulk at> 8/17/2010 11:18 PM >>>

Remind me…if you’re not using class-based matching, how are you assigning statics?  Some combination of Option 82 stuff?


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