Restricting ONT's Ethernet port to singe active IP address

Gideon Viator ktcisg at
Wed Apr 22 19:54:11 UTC 2009

I am also curious if this can be done. 


Gideon Viator

IT Systems Administrator 

Kaplan Telecommunications



From: dhcp-users-bounces at
[mailto:dhcp-users-bounces at] On Behalf Of Frank Bulk
Sent: Wednesday, April 22, 2009 14:47
To: dhcp-users at
Subject: Restricting ONT's Ethernet port to singe active IP address


In the cable modem and DSL world it's pretty easy to restrict the premise
equipment to a single IP address.  

-          In the cable modem world that can be assigned to the CM
configuration file or on the CMTS.  

-          DSL has a couple of flavors.  With PPPoA it's a single IP address
per vp/vc.  With PPPoE it can be nicely controlled on a per username or
connection basis.  With Cisco's RBE there's "DHCP Lease Limit per ATM RBE
Unnumbered Interface" to control handing out IP addresses.


But an RFC-1483-like FTTH implementation doesn't come with all those
benefits.  We could put a $50 CPE in each home with PPPoE and be responsible
for managing it, but we would prefer to let customers plug in their own
equipment into the ONT, but just get one IP address.


Option 82 support seems like the closest way to get it done, by creating
classes and handing out an static IP, but I understand the process
correctly, it requires generating a class for each Option 82 string and
assigning a static IP address.  That has the negatives of creating classes
in advance and giving out statics when I don't want to give out statics.


What it seems I want is to be able to use dynamic classes and hand out just
one IP address for each Option 82 string.  I know that dhcp is built around
using the MAC address as the standard identifier, but is there any solutions
to the challenge we're facing?


We also want our customers to be able to change CPE half-way through a lease
and not have to call the helpdesk to flush their legacy DHCP leases because
their new CPE doesn't get an IP address. ;)


I'm open for suggestions, and for those who can design an elegant solution
that doesn't require any re-compiling of code, a bounty.



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