[TriLUG] IPv6 equivalent to dhclient list

[Jym Williams Zavada]

Below is my response to Alan's query about what others are doing.  I'm not 
going to say it's the way everyone must do it, nor that it's the "right" 
way, and definitely not that it's the "best" way.  But it's been working out 
very well for me on my home LAN (with the IPv4 bit in place for some seven 
or so years now).  If you find it useful or appealing, you are more than 
welcome to scarf it whole or piecemeal according to your desire.  Also, I 
openly welcome ideas for improvement and comments regarding flaws, 
unforeseen pitfalls, etc.


- IPv4:

I use DHCP, but all permanent additions to the LAN get repeatedly assigned 
the same IP address based on MAC addresses.  All other nodes are considered 
"guests" that are given an available address from a narrow /28 subnet pool. 
I figure I'm far more likely to get hit by a stray comet than encounter the 
day where there's more than 14 guests glomming onto my network.  As to 
hostnames and DNS, all of them are hard-coded into my DNS service 
configuration, including the guests.  I've found that this makes it very 
easy to track nodes for monitoring and troubleshooting, and allows me to 
work with hosts by name.


- IPv6:

In addition to the automatic address a node uses based on it's MAC address, 
permanent additions to the LAN get configured to also use a contrived 
link-local address that corresponds to the IPv4 address.  And when needing 
access to/from the public Internet, I assign my pool of public IPv6 
addresses so that those particular nodes' IPv6 correspond to the 
aforementioned IPv4 address, with each node being configured accordingly. 
And as with IPv4, the DNS hostnames for my IPv6 nodes are hard-coded into my 
DNS service configuration.  Here's an example of what I mean (albeit 
the names and addresses have been changed "to protect the innocent".

For this example, let's assume my LAN is using 192.168.42.0/24 for the IPv6 
address range, and my son Samir comes home after buying a new Android 
tablet.  The first thing I do is get the MAC address from him.  Then I set 
up DHCP and DNS so that it gets IPv4 address 192.168.42.206 and a name of 
samirs-tablet.jimslan.local, or samirs-tablet for short.  I then have him 
configure it to also use a contrived IPv6 link-local address of

   fe80::f027:deff:fe00:206/64

in addition to the automatically configured link-local address.  And then 
the contrived address is given an IPv6 DNS record on the LAN DNS server so 
that the samirs-tablet name resolves to the manually contrived IPv6 address 
above, and an IPv6 PTR is created that resolves to the samirs-tablet 
hostname.  And knowning that Samir will want to be able to ssh from school 
via the public Internet back into his tablet on a day that he'll have 
forgotten to bring it to school, in spite of the fact that it has a homework 
assignment on it that is due that very day, I'll have already set up a DNS 
record with the DNS service provider that hosts my registered vanity domain 
name records so that samirs-tablet.example.com resolves to the public IPv6 
address that we'll have already configured the tablet to use.  Naturally, 
for convenience of setup and memorization, the IPv6 address will end with 
with :206, allocated from within the IPv6/64 range assigned to me by my IPv6 
tunnel broker or by my ISP.


On Tue, 6 Jan 2015 at 22:04, Alan Porter wrote:
[snipped]
> I'm just curious if others have made this transition, and if they have
> also felt like they are losing some of the old functionality... or if
> I am just "doing it wrong" (tm) and there is a better way to address
> IPv6 hosts by name.
>
> Alan