[BUGS] Anyone for IPv6?

[Christopher Vance]

On Tue, Aug 2, 2011 at 3:25 PM, Dean Hamstead <dean at fragfest.com.au> wrote:
> Hi Andrew,
>
>> Impending office moves and associated network migrations have me
>> thinking about (more like wondering idly, really) IPv6 again.
>> Is anyone here running an IPv6 internal network, rather than the
>> usual NAT-gated IPv4 one?  Is that even possible, or do you have

Been running IPv6 for years, both inside and outside the home. Have
found almost all traffic (except where I control both ends) is still
IPv4. The only email I got over IPv6 was NetBSD mailing lists and a
small amount of spam from China. Now I use gmail, that doesn't happen
any more.

> Yes, you can also to ipv6 to the internet regardless of your carrier thanks
> to a number of tunneling solutions. Many of which are trivial to configure
> on DD-WRT and other open source gateways, and become transparent to the
> machines on your LAN.

Of course, being BUGS, you might want to consider using a BSD router
with a basic ADSL modem. I prefer OpenBSD, but have used both Free and
Net for this in the past. Currently I'm using a Fritz!Box with native
IPv6 from Internode.

>> to maintain a working IPv4-NAT infrastructure so that your web
>> browsers and mail clients and what-not can find IPv4 hosts on
>> the wider internet?  (I.e., is there such a thing as an
>> IPv6-to-IPv4 NAT gateway?)
>
> There are mechanisms to deal with this, without resorting to NAT.

I expect local hosts to grow IPv6 capabilities without losing IPv4, so
you'll probably find your IPv4 local addresses are RFC1918 and NATted
outbound, while your IPv6 local addresses won't need translation or
NAT (unless your ISP is gouging or crazy).

>> Other idle questions: I believe that IPv6 does some form of
>> LAN-based auto-config, based on MAC addresses, right?  So
>
> Correct, all machines receive a link-local address. There are no broadcasts
> in ipv6, just multi-casts.

BSDs and Linux tend to use IPv6 autoconf, where your host uses its MAC
address to fill in the lower 8 bytes of its IPv6 address. Windows uses
a different method with some randomness in those bottom 8 bytes. That
method also rotates addresses every few hours.

>> there's no place for DHCP in an IPv6 network?  So what is the
>
> There is, DHCP is useful for providing org-local and internet addresses. As
> well as for provisioning customer devices (cable, dsl,
> ftth etc)

You can use DHCPv6 to provide local addresses instead of autoconf or
the other mentioned above, but I never bothered, since autoconf worked
so well for me. If your delegated nets keep changing you probably need
to work out how to get DHCPv6 from your ISP to change network
allocation on your router(s). I did some scripting when I thought it
was appropriate.

>> IPv6 way for doing name resolution?  Do you use zero-conf/avahi
>> to build the name database dynamically, or just manually enter
>> the auto-generated local IPv6 addresses into your tinydns
>> database, or ... (other options?)
>
> That is a limitation with the link-local mechanism.

Because the machines I want to connect to tend to be non-Windows, they
use autoconf and therefore static addresses. I just put them in the
relevant DNS zones manually.

If you care about connecting to Windows machines, you should probably
give them static RFC1918 addresses and use IPv4. Whatever you already
do for IPv4 and DHCP addresses into DNS may also be persuaded to work
for IPv6.

>> Anyone have any good pointers to war-stories and howtos on the
>> web?  It's been a while since I looked, but didn't have any joy
>> the last time I did.
>
> Check out this book from amazon, http://t.co/Ij1zoYE
> Of all the ipv6 books ive purchased, its the only one worth reading.

Can't comment on that book, since I've never seen it.

-- 
Christopher Vance