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AT&T doesn't like IPv6
03/26/09
I am trying to set up IPv6 on my Linux box which is connected to an AT&T DSL line.
Since the DSL modem only supports IPv4, I have set up an IPv6-to-IPv4 tunnel.
According to the IPv6 specs, this tunnel sends the IPv6 packets to the special "anycast" IPv4-address 192.88.99.1.
Update: The script I used to set up the tunnel is from here:
http://www.altocumulus.org/IPv6/
And the IPv6 routing table:
$: route -A inet6 Kernel IPv6 routing table Destination Next Hop Flags Metric Ref Use Iface ::1/128 :: U 0 135 1 lo ::75.3.241.4/128 :: U 0 0 1 lo ::/96 :: U 256 1 0 tun6to4 2002:4b03:f104::1/128 :: U 0 0 1 lo 2002::/16 :: U 256 0 0 tun6to4 2000::/3 ::192.88.99.1 UG 1 109 0 tun6to4 fe80::200:5aff:fe71:6c07/128 :: U 0 0 1 lo fe80::211:11ff:febe:743e/128 :: U 0 0 1 lo fe80::/64 :: U 256 0 0 eth0 fe80::/64 :: U 256 0 0 eth1 fe80::/64 :: U 256 0 0 tun6to4 ff00::/8 :: U 256 0 0 eth0 ff00::/8 :: U 256 0 0 eth1 ff00::/8 :: U 256 0 0 tun6to4
I tried an nslookup to see if things work:
$: nslookup
> set querytype=ANY
> ipv6.l.google.com
Server: 192.168.0.1
Address: 192.168.0.1#53Non-authoritative answer:
ipv6.l.google.com has AAAA address 2001:4860:b002::68
So far, so good.
I then tried to ping ipv6.l.google.com, and that fails:
$: ping6 ipv6.l.google.com
PING ipv6.l.google.com(2001:4860:b002::68) 56 data bytes
^C
--- ipv6.l.google.com ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 2999ms
Seems that AT&T somewhere does not route to 192.88.99.1 correctly.
A traceroute shows:
$: traceroute 192.88.99.1
traceroute to 192.88.99.1 (192.88.99.1), 30 hops max, 38 byte packets
1 192.168.0.1 (192.168.0.1) 0.389 ms 0.295 ms 0.286 ms
2 adsl-75-3-255-254.dsl.irvnca.sbcglobal.net (75.3.255.254) 9.080 ms 6.618 ms 5.788 ms
3 dist1-vlan60.irvnca.pbi.net (67.114.48.130) 6.760 ms 6.202 ms 6.407 ms
4 bb1-p2-1.ksc2mo.sbcglobal.net (151.164.42.7) 5.838 ms 6.740 ms 6.345 ms
5 ex1-p13-0.eqlaca.sbcglobal.net (151.164.188.138) 7.729 ms 7.855 ms 7.360 ms
6 asn6939-he.eqlaca.sbcglobal.net (151.164.251.86) 7.319 ms 15.424 ms 7.344 ms
7 10gigabitethernet1-3.core1.pao1.he.net (72.52.92.21) 17.020 ms 16.658 ms 16.775 ms
8 * * *
...
So it seems that AT&T is handing this off to he.net, and there it just hangs.
Pretty lame.
I had an online chat with AT&T tech support, and they weren't much help, either. The first thing they said, of course, was "we don't support Linux". When I pointed out that Windows Vista also has IPv6 built-in, and that my question was about IPv6, not Linux, the tech support guy was staying on, but still, couldn't get me any useful information.
Update: The problem turned out to be the DSL modem, which seems to filter the tunneled IPv6 packets.
5 comments
This is very very very interesting. AT&T / HE handoff broken. How drool.
I have resorted to just doing OpenVPN and GRE tunnels these days. *sighs*
Would be nice if you could send ipcpv6 and get a /64 from the PoP. 
I keep meaning to try that and see if it’s that simple.
Please keep us posted on your issue.
You should try posting on NANOG about this. I imagine they would be quite interested.
This is exciting…. they actually might be setting up a v6 tunnel broker on this continent!
http://www.corp.att.com/gov/solution/network_services/data_nw/ipv6/ appears to support that AT&T is building a v6 peer/tunnel.
Sorry if it seems I’m spamming your blog. This is just so cool and your the first person with a half way decent post on the issue.
Yes, I have come across that link as well, and pointed it out to the tech support guy while I was still in the online chat with him.
My guess is they are going to charge extra for it, though 
Just because the traceroute “dies", doesn’t mean that routing is broken between AT&T and HE. I am able to ping the HE anycast service just fine from several locations within AT&T Internet Services (AS7132). Anyhow, I left you an email via the contact link on your blog offering some help. Let me know.
