Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

DHCPv6 and Manual Bindings

With DHCPv6, do manual address bindings not apply?  I see manual bindings for prefix delegation but none for addresses.

In dhcpv4, there was the ability to specify a client-id (or hardware-address) and then use the command 'host a.b.c.d' to assign a specific address to a specific host.

In studying dhcpv6, I do not see a similar capability.

Thanks

Everyone's tags (3)
6 REPLIES
New Member

Re: DHCPv6 and Manual Bindings

Anyone?

New Member

Re: DHCPv6 and Manual Bindings

Free Beer!

New Member

Re: DHCPv6 and Manual Bindings

Wow, all those Cisco folks and CCIEs out there and nobody knows! I have either stumped or bored the world's experts.

Does anyone know the answer to my question?

New Member

Re: DHCPv6 and Manual Bindings

Hope this helps. 

http://www.cisco.com/en/US/tech/tk872/technologies_white_paper09186a00801e199d.shtml#wp41640

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-dhcp.html

If I understand your question, you are asking if you can do a one-to-one mapping between a client and an IPv6 address.  Are you looking for this mapping to be a global, link local or unique local?  What is the driver behind this requirement?  If you have the DHCPv6 configured to hand out a /64 prefix then using the manipulation on the MAC address, you will know (predictably) what the address will be:  .

Here is what Cisco has to say about their implementation of DHCPv6 (from the first link):

The Cisco IOS Software DHCPv6 function runs in routers. It is based on RFC3315 DHCPv6 specification. Prefix Delegation [PD] and DNS [DNS] DHCPv6 options are supported and allow distribution of a prefix, as well as a list of DNS servers and domain names.

The Cisco IOS Software DHCPv6 client and server are specifically intended as a PD solution and do not implement the entire DHCPv6 protocol. Cisco IOS Software DHCPv6 currently implements PD, the rapid-commit mechanism, stateless DHCPv6 ("DHCPv6-lite"), and the following:

Client Identifier option

Server Identifier option

Option Request option

Preference option

Status Code Option

Rapid Commit option

Identity Association for Prefix Delegation option (IA_PD option)

IA_PD Prefix option

Domain Name Server option

Domain Search List option

New Member

Re: DHCPv6 and Manual Bindings

Thank you , that is helpful. The server is handing out IA_NA and chooses the 'host' bits (those beyond the address prefix specified in the dhcpv6 pool.)

I was looking to see if I can also control the lower 64 bits being handed out.

New Member

Re: DHCPv6 and Manual Bindings

I am not aware of a DHCPv6 server that does this.  I believe that the expectation and design for IPv6 is that the host is responsible for this (per RFC 4862).

   This document specifies the steps a host takes in deciding how to
   autoconfigure its interfaces in IP version 6.  The autoconfiguration
   process includes generating a link-local address, generating global
   addresses via stateless address autoconfiguration, and the Duplicate
   Address Detection procedure to verify the uniqueness of the addresses
   on a link.

I hope that helps.  To be clear, I am speaking of link-local addresses.  Global addresses are a different matter when mapped to a DNS name.  I would expect that any FQDN name would resolve to a static IPv6 address (or by some DDNS means).

712
Views
5
Helpful
6
Replies