Ipv6 / DNS questions

[Matthew Seaman]

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.

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

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