Ipv6 / DNS questions

[Gary Palmer]

On Fri, Jun 02, 2017 at 09:56:28AM +0100, Matthew Seaman wrote:
> On 06/02/17 02:49, Karl Denninger wrote:
> > Is there a dynamic DNS update method associated with Ipv6's address
> > assignment system?  Since the assignment is "stateless" it obviously
> > (and does, in my experience!) move.  I can deal with it via a couple of
> > shell scripts, and there are only a couple of hosts where it matters,
> > but this would dramatically simplify the IPv4 gameplaying that's
> > necessary to have something behind a gateway router while on a "globally
> > visible", but possibly changing "at whim", IpV6 address.
> 
> Assuming that you always get the same /64 assigned to your gateway, then
> the address SLAAC assigns to your server will be constant so long as
> you're on the same hardware, since the SLAAC address is generated from
> the network prefix and the MAC address of the NIC.  In that case, it
> often suffices to update the DNS manually.

Only if

ipv6_privacy="YES"

is not set.

Regards,

Gary

> 
> If that doesn't work for you, then while there isn't a DNS update
> mechanism built into SLAAC, there is one in DHCP6.  That relies on the
> dhcp server being able to make dynamic DNS updates via nsupdate(1).  Of
> course, if you have all the keys etc. set up to be able to use
> nsupdate(1) you could fairly easily add a 'dns-update' rc script on your
> host to push the hosts' IPv6 address into the DNS.
> 
> The other fairly common approach would be to use a network configuration
> system like ansible or puppet that can gather facts about a machine
> (such as the IPv6 address) write them into a DNS zone file.
> 
> 	Cheers,
> 
> 	Matthew
>