[ipv6hackers] Question on DHCPv6 address assignment

Scott Hogg scott at hoggnet.com
Sat Feb 1 05:13:17 CET 2014


I apologize for not sounding very authoritative on the subject.  I don't 
profess to be a DHCPv6 expert; I am just trying to answer Fernando's 
question to help him out.  Maybe someone who works for a company that makes 
DHCPv6 software would be a better spokesperson.

Different versions and different manufacturers of DHCPv6 servers have 
implemented slightly different features.
Some of the DHCPv6 specifications don't cover some of these minor details so 
it is left up to the implementer.

Microsoft DHCP server, BIND 9.X, Cisco Network Registrar (CNR) 7.X, and 
Infoblox NIOS all hand out randomized identifiers.
Earlier versions of Incognito Broadband Command Center (BCC) handed out 
sequential addresses.
Earlier versions of these products may have also handed out sequential 
interface identifiers.

I have not done a comprehensive survey of all versions of all manufacturers' 
DHCPv6 servers.
Nor have I performed this research with every possible permutation of DHCPv6 
client software version/manufacturer.

Scott

-----Original Message----- 
From: Mark ZZZ Smith
Sent: Friday, January 31, 2014 7:57 PM
To: IPv6 Hackers Mailing List ; Fernando Gont
Subject: Re: [ipv6hackers] Question on DHCPv6 address assignment



Scott, what specific DHCPv6 server are you describing? You're using a lot of 
"believe", "to my knowledge", etc., which sounds a bit second hand. I think 
Fernando is after first hand experience and details of specific 
implementations.

Regards,
Mark.


----- Original Message -----
> From: Scott Hogg <scott at hoggnet.com>
> To: Fernando Gont <fgont at si6networks.com>; IPv6 Hackers Mailing List 
> <ipv6hackers at lists.si6networks.com>
> Cc:
> Sent: Saturday, 1 February 2014 11:27 AM
> Subject: Re: [ipv6hackers] Question on DHCPv6 address assignment
>
> Yes, I believe it works just like DHCP for IPv4 in that respect.
> However, each DHCPv6 server could be configured for different behavior for
> lease times, renewals, etc.
> The ICMPv6 RA message would dictate that the clients perform stateful
> address assignment (DHCPv6), but a host could choose to ignore that
> recommendation and proceed with a static IPv6 address.
> That is why DAD is important in all cases prior to assuming use of an IPv6
> address.
>
> Scott
>
>
> -----Original Message----- 
> From: Fernando Gont
> Sent: Friday, January 31, 2014 3:33 PM
> To: IPv6 Hackers Mailing List
> Cc: scott at hoggnet.com
> Subject: Re: [ipv6hackers] Question on DHCPv6 address assignment
>
> Hi, Scott,
>
> On 01/31/2014 06:46 PM, Scott Hogg wrote:
>>  1) To my knowledge, most DHCPv6 servers hand out randomized interface
>>  identifiers within the scope range.
>>  2) Hosts typically renew their lease at 50% of the lease time.  If the
>>  lease time is one week, then, most hosts that are joined to the network
>>  regularly will renew their least at 3.5 days and keep a fairly stable
>>  address.
>
> Same thing after boot-strapping? i.e., last-used address is renewed as
> opposed to getting a new randomized address?
>
> Thanks!
> -- 
> Fernando Gont
> SI6 Networks
> e-mail: fgont at si6networks.com
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>
>
>
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