dhcpv6 => relay, encapsulated vendor options discarded

Benoit Panizzon benoit.panizzon at imp.ch
Thu Nov 29 10:52:58 UTC 2012

Hello World

After struggling with the ISC DHCP Server Version 4.2.4-P2 for a while, using 
it in a DOCSIS Cable Network environment we had one of our developer look at 
the isc code to find out why the needed suboptions (4419 containing 1026) are 
always empty.

In a Cable Network the Flow of Events is as follows:

Customer CPE (receiving RA with 'statefull' flag)
Customer CPE (sending DHCPv6-Solicit Message
Customer Modem (Adding Encapsulated Vendor Option containing some information 
needed to correctly provision that modem)
CMTS (DHCP Relay, Encapsulating the while package in a DHCPv6 Forward Relay 
ISC DHCP Server (Reading the encapsulated message and extracting only the 
original DHCPv6 Solicit Message sent from the client. Discaring the viso 
suboptions added by the Customer Modem).

- Is this a known Bug?
- Is this somehow intended behaviour?
- Is there a fix or patch for the issue?

And something I should probably not ask on this list?

- Does anyone know another DHCPv6 Server which gives access to those options?


Benoit Panizzon
I m p r o W a r e   A G    -    

Zurlindenstrasse 29             Tel  +41 61 826 93 07
CH-4133 Pratteln                Fax  +41 61 826 93 02
Schweiz                         Web  http://www.imp.ch

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