Re: dhcp6 and fqdn support (for dns)

[Gene Czarcinski <gene czarc net>]

On 09/15/2012 10:13 AM, Gene Czarcinski wrote:
> I am trying to set up an IPv6 virtual network using dnsmasq to support 
> the dhcp and dns.  Recently (the last couple of releases) dnsmasq has 
> supported dhcp with updating dns.
>
> I have gotten it so that the IPv6 addresses are assigned correctly but 
> I have been driving myself nuts trying to figure out why it does not 
> update the dns with the IPv6 address.  I have come to the conclusion 
> that it is because NetworkManager does not send the fqdn.
>
> I am not sure if fqdn is required or if the hostname would be OK. 
> However, in looking at some of the dhcp documentation for options, it 
> appears that fqdn should be specified and not just the hostname.
>
> Before I turn in some bug reports and look at the code, is my 
> understanding correct?
I have done some additional testing.

I suspected that something was missing from the NetworkMananger support 
for IPv6 dhcp.  Here is what I did the prove it.

1.  Stop NetworkManager.

2.  Make sure that the ifcfg-eth0 file has DHCP_HOSTNAME==xxxx and 
DHCPV6C=yes are specified.

3. Slightly modify the ifup-eth network script to change the "-H" to 
"-F" on the "dhclient -6" line.

4. do "ifup eth0"

5  Use wireshark (or equivalent) to trace the packets on the interface.  
See that fqdn info is being passed whereas it was not when 
NetworkManager did everything.

6.  With dnsmasq I now have IPv6 addresses added to the dns.  In 
examining various documents but not doing any testing, I believe that 
dhcpd-v6 will need to info to support dynamic dns updating for IPv6 
addresses.

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.

OK, bug or feature?

Gene