[colug-432] CMH TW providing residential ipv6

R P Herrold herrold at owlriver.com
Tue Jun 24 16:07:19 EDT 2014

On Tue, 24 Jun 2014, Rob Funk wrote:

> > in this block: 
> > 	2605:a000:110f:807e:xxxx:xxx:xxxx:xxxx
> For those of us without much ipv6 experience, how could you tell that
> TWC was giving you ipv6 address space? Did you have to set up anything
> ipv6-specific first?

This was totally hands off, with that particular modem -- it 
'just happened'

I 'went looking', after another person in town here and I 
noticed some interesting logfile entries when debugging a 
connectivity issue.  When running down causes, found ipv6 
entries in a logfile

Here is an example from me connecting to an outside host

[root at charles ~]# grep herrold /var/log/secure | \
	grep publickey | grep -E '[:][[:alnum:]]{4}[:]'
Jun 22 18:20:30 charles sshd[17712]: Accepted publickey for 
herrold from 2605:a000:110f:807e:xxxx:xxxx:xxxx:xxxx port 
49592 ssh2
Jun 22 21:24:55 charles sshd[6837]: Accepted publickey for 
herrold from 2605:a000:110f:807e:yyyy:yyyy:yyyy:yyyy port 
49449 ssh2

The xxxx and yyyy blocks vary in this example, but I was doing 
keyed access from two different hosts behind that Apple 
Airport Extreme -- it does not confirm or deny an answer to my 
persistence question

> I have my own Zoom cable modem on TWC, in bridge mode connected to an
> OpenWRT 12.09 router. So far the only ipv6 addresses I see in ifconfig
> on OpenWRT are marked Scope:Link.

* nod * those 'Scope:Link' start with: FE and have a /10 bit 
CIDR netmask -- that block were present in the raw material of 
my prior post as well but I had trimmed it out as out of scope 
(link local can be used by self-organizing network collision 
domains).  Properly, content with that prefix will not cross a 
boundry router demarc, just as with RFC 1918 assignments and 
good sysadmin [OARnet used 10.x.x.x for its internal backhaul 
and meshing, for example]

You should also see them with a couple of stock deployment 
centos boxes, along with the 169.254.x.x/16, and Avahi 
enabled, and ipv6 NOT disabled in /etc/sysconfig/network -- 
the initscripts are pretty smart ;)

-- Russ herrold

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