Re: dhcp6 and fqdn support (for dns)

[Gene Czarcinski <gene czarc net>]

On 09/17/2012 12:05 PM, Jiri Popelka wrote:
> On 09/16/2012 09:55 PM, Gene Czarcinski wrote:
> > BTW, from the info in the dhcp-options man-page, I believe that 
> > NetworkManager should be doing "send fqdn.fqdn" instead of "send 
> > host-name" for IPv4.  This should be with a plain name ... not a 
> > qualified name.  See the man-page.
> The story behind this is
> https://bugzilla.redhat.com/show_bug.cgi?id=694758#c20 (NetworkManager)
> https://bugzilla.redhat.com/show_bug.cgi?id=697877 (initscripts)
>
> > OK, bug or feature?
>
> Well, me and the original reporter of those bugs had suggested to 
> "send fqdn.fqdn" when $(hostname) was FQDN and "send host-name" 
> otherwise, but Bill Nottingham (initscripts) decided to always "send 
> host-name". So I thought it would be better for NM to stay consistent 
> with initscripts.
> Read those BZs and if you think the behavior is wrong you could try to 
> re-open them.
I have not gone back to look into the history of what should or should 
not be sent.  I only looked at what is said in the current (Fedora 17,  
dhcp-common-4.2.4-9.P1.fc17) dhcp-options man page.
------------
option fqdn.fqdn text;

 Specifies  the  domain name that the client wishes to use.   This can 
be a fully-qualified domain name, or a single label.   If there is no 
trailing  ´.´  character  in the name, it is not fully-qualified, and 
the server will generally update that name  in some  locally-defined domain.
-----------

It also says that "options fqdn.hostname" and "option fqdn.domainname" 
should never be set.

When I got things to work, there was a lot of options in the lease file 
in addition to fqdn.  I am not sure exactly what needs to be specified 
except that for IPv6 if I specify "-F <homtname>" on the dhclient 
command line, things work.  For IPv7 "-H <homename>" seems to work.

Regardless, as things now work I do not get dynamic dns update for IPv6 
(works fine for IPv4).  This has been with dnsmasq as the dns and dhcp 
server.  I am not setting up testing on qemu/kvm/libvirt with a guest 
running named and dhcpd instead of dnsmasq.  My expectation is that it 
will not do dynamic dns either.

My reason for pushing this is that while using radvd to help with IPv6 
address assignment works for a client-only situation, it soon falls 
apart when I have a bunch of systems referring to each other. For IPv4 
using addresses only is painful, for IPv6 it is impractical.

I believe that such situations will needs either a IPv6 dhcpd with DDNS 
to named or a dnsmasq.  I do not know, there might be other packages out 
there but these seem to be common.

Gene