Supported format for Client Identifier.

[sthaug at nethelp.no]

> > Since RFC4361 supersedes RFC2132, is it safe to ask Redback to  
> > implement it using the format specified in RFC 4361?
> 
> Nothing is ever perfectly safe, but the RFC4361 client identifier  
> format is backwards-compatible with RFC2132, so it would take a very,  
> very broken implementation to choke on it.

It is backwards compatible *except* for the fact that the "standard"
DHCPv4 format of hardware type (1) followed by the 6 byte MAC address
is no longer permitted, as far as I can see.

As has been discussed on this list, see for instance the threads

"host-identifier with IPv6"
https://lists.isc.org/pipermail/dhcp-users/2009-February/008088.html

"DHCPv6 host-identifier, the Never Ending Thread: A Summary"
https://lists.isc.org/pipermail/dhcp-users/2009-March/008307.html

some people *really* want to be able to get the MAC address of the
client, and the RFC 4161 format removed this possibility.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no