host-identifier with IPv6

Marc Perea marccp at
Tue Mar 3 17:38:34 UTC 2009

This isn't exactly related to the thread, but...

>>Message: 5
>>Date: Mon, 2 Mar 2009 23:22:42 -0700
>>From: Ted Lemon <Ted.Lemon at>
>>Subject: Re: host-identifier with IPv6
>>To: "frnkblk at" <frnkblk at>, Users of ISC DHCP
>>	<dhcp-users at>
>>Message-ID: <9CFAE039-1AA8-4B83-B35E-E98D3C25AC2F at>
>>Content-Type: text/plain; charset="us-ascii"; format=flowed; delsp=yes
>>On Mar 2, 2009, at 9:17 PM, Frank Bulk wrote:
>>> I'm not aware of any MSO handing out IPs to their CMs or CPE based on
>>> circuit ID.  It's my understanding that everyone uses MAC addresses.
>>That's not precisely what I was saying.   Nobody uses (or should use)  
>>the circuit ID to assign IP addresses.   What I mean is that they use  
>>the circuit ID to figure out who you are (that is, whether or not your  
>>account is current, etc).   Since this information is handed to the  
>>DHCP server by the relay agent, it's dead easy to track.

I work for an ISP where we do exactly that; we assign IP addresses based on a client request matching a class that is defined by their agent.circuit-id, with a pool of a single IP address designated for that customer. Why should I not use the circuit ID to assign the IP?

On the corporate side, chalk us up as another ISC dhcpd user who both would like to use some flag to set MAC (hardware address) as the primary key in the leases database for v4 and another proponent of having some way to reliably use the MAC of a new device in dhcp administration of v6 in the future. We haven't yet begun v6 rollout and likely won't until forced to by govt. mandate. By the sounds of it, this won't at all be a "fun" upgrade when the time comes.

Marc Perea
Network Support Engineer
SRT Communications, Inc.
marccp at

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