IPv6 Subnetting

[Jonas]

Here's my route -6:

jonas@kubacer:~$ route -6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
fe80::/64                      ::                         U    256 0     0 eth1
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     1 lo
fe80::1af4:6aff:fe23:7b76/128  ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth1
::/0                           ::                         !n   -1  1     1 lo

Sorry for not being able to help more, this is all greek to me :S

I'm happy to help in anyway I can, just gimme the lines to analyse, and maybe learn a thing or two

b.r

jonas

[GreyGeek]

Here's my route -6:

jonas@kubacer:~$ route -6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
fe80::/64                      ::                         U    256 0     0 eth1
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     1 lo
fe80::1af4:6aff:fe23:7b76/128  ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth1
::/0                           ::                         !n   -1  1     1 lo

Sorry for not being able to help more, this is all greek to me :S
....

So, I't pretty much greek to me as well, Jonas. I'm just tinkering around... luckily IPv6 isn't toxic or explosive.

I noticed that your setup doesn't have a UG on your IPv6 ff00::/8 eth1 connection.

And, the ip addr command shows a teredo address of 2001:0 ..... but your IPv6 routing table doesn't include it. Yet, you get out and have a 10/10 connection.

[COLOR=#333333]4: teredo: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1280 qdisc pfifo_fast state UNKNOWN qlen 500[/COLOR]
[COLOR=#333333]link/none [/COLOR]
[COLOR=#333333]inet6 [/COLOR][COLOR=#ff0000]2001:0[/COLOR][COLOR=#333333]:53aa:64c:c47:3ccc:d1c4:ceb7/32 scope global [/COLOR]
[COLOR=#333333]valid_lft forever preferred_lft forever[/COLOR]
[COLOR=#333333]inet6 fe80::ffff:ffff:ffff/64 scope link [/COLOR]
[COLOR=#333333]valid_lft forever preferred_lft forever
[/COLOR]

Mine shows I have my IPv6 sixxs device as a gateway:

::/0                           2001:4978:f:580::1         U[COLOR=#ff0000]G[/COLOR]   1024 0     0 sixxs

Apparently without a gateway and no IPv6 DNS, you communicate with IPv6 networks and have DNS resolution in them. It must all be due to your ISP.

Question:
If you do:
sudo ifconfig teredo down
or
sudo service miredo stop

do you still get 10/10?

[Jonas]

sudo ifconfig teredo down & sudo service miredo stop

Give me IPv6 result of 0/10

b.r

Jonas

[GreyGeek]

sudo ifconfig teredo down & sudo service miredo stop

Give me IPv6 result of 0/10

Ah, then your IPv6 connectivity is totally dependent on the Teredo tunnel and your DNS servers (which give you the 10th 10) are supplied by your ISP. This suggests that IF your cable modem is DOCSIS 3.0 compatible, since your ISP is IPv6 already, that:

https://wiki.ubuntu.com/IPv6#Native_IPv6_connections

Native IPv6 connections

Contact your Internet Service Provider to see if they offer IPv6 yet. Only a few Internet Service Providers (ISP) currently offer native IPv6 service, though by 2015 probably all of them will.
If your uplink involves a wifi router or broadband modem, those devices will need to support IPv6. Cable-Modems need to support DOCSIS 3.0 or 2.0+IPv6. As of 2010, very few DSL-Modems support IPv6; this will change by 2012.
If your hardware or ISP does not support native IPv6, which is the best kind, you might still be able to use IPv6 tunneled over IPv4 instead.

and you could use DHCPv6 to dispense an IPv6 address.

[Jonas]

[FONT=courier new]
Ah, then your IPv6 connectivity is totally dependent on the Teredo tunnel and your DNS servers (which give you the 10th 10) are supplied by your ISP. This suggests that IF your cable modem is DOCSIS 3.0 compatible, since your ISP is IPv6 already, that:

https://wiki.ubuntu.com/IPv6#Native_IPv6_connections


and you could use DHCPv6 to dispense an IPv6 address.

I have fiber cable - only thing I "plug in" is the router a D-Link DIR 655, which is quite a old model. Sites seem to load slower with IPv6 enabled , I've had this trouble before so I used to disable it.

b.r

Jonas

[GreyGeek]

An aside: Somehow my Chromium browser stopped preferring IPv6 over IPv4, and I't get an error message from some sites saying that I didn't have IPv6 so they couldn't display the page. I tried with FireFox it the page would display. I also "ping6"ed the websites and both ends of my tunnel and got echos back.

FireFox has a setting one can use to enable a preference for either IPv6 or IPv4. Chromium *used* to have such a setting (in the url enter "chrome://net-eternals" and on that page select "DNS". The DNS page did have a button that enabled IPv6. Now, it doesn't. Chromium now shows "ADDRESS_FAMILY_UNSPECIFIED", which causes it to consult /etc/gai.conf to determine which IP protocol to try first. It used to prever IPv6. Now it trys IPv4 first.

The man pages to gai.conf are not very extensive nor are they understandable. An example is given but no explanation. After some experimentation/trial/error I come across settings that worked to make Chromium try IPv6 first:

label ::1/128       0
label 2002::/16     1
label 2001:0::/32 2
label ::/0          3
label ::/96         4
#label ::ffff:0:0/96 5
#label fec0::/10     6
#label fc00::/7      7


#
.....
#
precedence  ::1/128       50
precedence  ::/0          40
precedence 2001:0::/32  35
precedence  2002::/16     30
precedence ::/96          20
#precedence ::ffff:0:0/96  10

I added the "... 2001:0::/32 2" lines to both label and precedence. My assumption is that getaddressinfo() would try them in the order of the index numbers at the end of each line. True or not, Chromium now tries the IPv6 protocol first.

[67GTA]

If you are using dd-wrt, the dev has stopped including IPV6 support. This drove me nuts for a while until I figured it out.>

[GreyGeek]

If you are using dd-wrt, the dev has stopped including IPV6 support. This drove me nuts for a while until I figured it out.>

Did the dev say why?

[67GTA]

I haven't found any official statement. I ran across a post on their forums where every one was asking where IPV6 had gone. All of the older builds had support, but was dropped somewhere down the line. You are supposed to be able to set it up, but my Linksys WRT160n doesn't have the ram. I already have to use the mini build to run dd-wrt on it. http://www.dd-wrt.com/wiki/index.php/IPv6

[SteveRiley]

What about OpenWRT? Might be a suitable alternative.

[GreyGeek]

What about OpenWRT? Might be a suitable alternative.

Apparently the same way I get it with Kubuntu: http://wiki.openwrt.org/doc/howto/ipv6

Obtain IPv6 support

Follow ipv6.essentials to obtain full IPv6 support. Then come back and read about the configuration here:
There are two big, different steps:

1. Set up a working IPv6 connection on the OpenWrt router, either by tunneling (SixXs, TSP, 6to4), or natively
   
2. Propagate the IPv6 subnet to the LAN with RADVD or DHCPv6.

Native IPv6 access

For this, you need to obtain an IPv6 address from your ISP. Technically this could be a /128 prefix (exactly one IPv6 address), but according to rfc6177 this should be a /64 prefix. You may also get bigger range, like /56 or /48. Within this range you may use all the IPv6 addresses to your liking without any NAT-induced headaches.

Here is someone's attempt: https://forum.openwrt.org/viewtopic.php?id=27541

I was looking for information about configuring my router (originally Netgear WNDR3700) for supporting a static 6in4 tunnel from SixXS for getting the IPv6 connectivity. The router is currently running OpenWrt Backfire 10.03.1-rc4, published in November 2010, the rc4 version of the forthcoming Backfire Interim Release 1.

Current OpenWrt Backfire 10.03.1-rc4 has an installable package for supporting the 6in4 tunnels, which should make the process relatively easy. However, finding the exactly correct configuration is not that easy. I found useful information in internet, but it was scattered around and to some extent also outdated or incomplete. I write this article to summarize my findings and to list my configuration as an example for others trying to do the same.

Additionally, the rc4 version does not enable configuring some of the required steps through the Luci GUI, so some tasks have to be done by editing configuration files manually.

Background assumptions: you have a "Static" 6in4 tunnel with a fixed tunnel endpoint from SixXS. You also have a subnet, which is routed through that tunnel. You also have installed the OpenWrt to the router.

Main steps in the process:
Configuring the tunnel
Configuring iptables to make sure that the tunnel stays up
Configuring IPv6 address autoconfiguration inside local LAN by using RADVD
Configuring ipv6 firewall - ip6tables
...

... and it goes on. With that advice and installing miredo I can get a dual stack.

[GreyGeek]

If you are using dd-wrt, the dev has stopped including IPV6 support. This drove me nuts for a while until I figured it out.>

I did some searching and found this:http://www.dd-wrt.com/wiki/index.php...D-WRT%3F#Notes

(5)Apparently, IPv6-related features DO NOT work by default in DD-WRT v24. See IPv6 on v24.

That link led to this one:
http://www.dd-wrt.com/wiki/index.php/IPv6_on_v24
This link states:

IPv6 On V24


UPDATE: If you are just trying to get IPv6 working (6to4) on v24 sp1, please view this page:
http://www.dd-wrt.com/wiki/index.php/IPv6#6to4_Setup

...
The currently recommended K2.6 big images ship with basic IPv6 support. That means that you're able to activate the IPv6 IP stack for routing and static tunnels. What's missing are the ip6tables kernel modules and the userland tools needed. It's possible to add the missing parts but that requires some basic Linux system knowledge. It's assumed here that you have /jffs mounted and a few megs of space available and you know how to use ipkg.Please note: What you've to download still depends a lot on the hardware you're running on!

Kernel modules

The currently recommended build r14929 ships with a patched Linux kernel with a version number set to 2.6.24.111. Since the kernel modules from OpenWRT have the magic version information set you can't use the kmod packages from OpenWRT. Because of the version mismatch insmod won't load those modules.
This leaves you with two options:

1. Trust lazytom and download his set of modules from the forum http://www.dd-wrt.com/phpBB2/download.php?id=16285
2. If you don't trust random people on the internet (which is a good thing) you'll find an introduction on how to build these modules yourself in this blog post http://blog.dest-unreach.be/2010/12/...kernel-modules

.....

Which leads to:

6to4 is a mechanism which assigns a large block of IPv6 addresses to every IPv4 address on the Internet. You can use 6to4 with DD-WRT to give every computer on your network a globally-accessible IPv6 address without the need to configure explicit tunneling. This should be the simplest method to add IPv6 to your entire network.
Important Reminders :

• In order to use ipv6, you need the Standard or VoIP version of DD-WRT, as these are currently the only ones which support both IPv6 and radvd.
• The detailled configuration steps are targeted toward users with a basic DHCP connection for the WAN part. So, if using PPPoE will require replacing vlan1 with ppp0 in each instance. Other connection types will vary.
• When using DD-WRT standard on a router with 4MB Flash, there is no space available for jffs.
• This guide only relies on nvram variables, so that jffs is not needed.
• The configuration shown below has been verified to work properly on v24 sp1 stable (standard)

...

and we are back to tunnels again.

[SteveRiley]

We're living in an IPv4-IPv6 transition world right now. It will be almost impossible to avoid tunnels until IPv6 is running natively everywhere.

[67GTA]

I've looked around, and I think only tomato has full ipv6 support, but you still have to fiddle with it. It wasn't worth the trouble to me. I just added this to the list of "Honey, this is why I need a new router".