Server addressing for renumbering ease

[Ben Jencks]

On Sun, Nov 7, 2010 at 15:22, Mohacsi Janos <mohacsi at niif.hu> wrote:
> On Sat, 6 Nov 2010, Ben Jencks wrote:
>
>> According to [1], they used EUI-64 addressing on their servers so that
>> they could renumber easily. The common objection to that is that you
>> wouldn't want to change DNS anytime you swapped a NIC (and thus a mac
>> address). The obvious alternative is static addressing, but that makes
>> renumbering a pain. There's also DDNS, but that seems like a bigger
>> headache than either of the above [2]. What are people here doing?
>
> Using autoconfigured addresses on servers are bad idea. If you want to
> generate big problems for yourselves, use it on DNS servers....

For DNS servers it would obviously make things difficult, but there
are massively fewer DNS servers than other servers. Touching every DNS
server during a renumbering seems fairly reasonable; touching every
server can be infeasible.

Why do you find it a bad idea for other servers? Just the switching
NICs/mac address dependence issue? I'll grant that SLAAC is another
moving part, but it's a pretty simple protocol that I'd be willing to
trust with numbering my servers.

Another thought I had is that with the rise of virtualization, SLAAC
actually starts to make more sense for virtual machines. While
replacing a NIC in a physical server isn't uncommon, since VMs have
virtual mac addresses they can reasonably be expected to keep the same
mac, and thus the sam SLAAC IP, for the lifetime of the VM.

-Ben

> In 6diss/6deploy training material we are advocating using static addresses
> for servers:
> http://www.6deploy.eu/tutorials/131_IPv6_deployment%20consideration_v0_8.pdf