Last week I installed Miredo and configured my system to handle IPv6 through 6to4 tunneling. It was easy and it worked well.
So I decided I'd give Hurricane Electric's IPv6 connection a try. I've had a lot to learn, and I thought I had it all running (with a great deal of help from a very patient person at Hurricane: my LinkSys E3200 didn't like IPv6).
But now, when all should be good, after I uninstalled Miredo and Teredo and whatever else, I find that there is "6to4 tunneling - another automatic tunneling," which I need to remove from my box. But I have no idea where or what it might be.
Connected to my computer are a couple printers, an external hard drive, and a router (which has no settings for IPv6). All of these are, I think, innocent in this matter.
$ ifconfig eth0 Link encap:Ethernet HWaddr 00:21:9b:1c:26:bb inet addr:192.168.1.104 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: 2002:42db:c22c:0:221:9bff:fe1c:26bb/64 Scope:Global inet6 addr: fe80::221:9bff:fe1c:26bb/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1427 errors:0 dropped:0 overruns:0 frame:0 TX packets:1342 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1152240 (1.1 MB) TX bytes:177497 (177.4 KB) Interrupt:20 Memory:fdfc0000-fdfe0000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:12 errors:0 dropped:0 overruns:0 frame:0 TX packets:12 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:720 (720.0 B) TX bytes:720 (720.0 B) $ ip -6 route show 2002:42db:c22c::/64 dev eth0 proto kernel metric 256 expires 24sec fe80::/64 dev eth0 proto kernel metric 256 default via fe80::c2c1:c0ff:fec6:3308 dev eth0 proto kernel metric 1024 expires 1794sec hoplimit 64
So, how can I get rid of 6to4 tunneling, when I don't even know where it is? Is there someplace to look and find out what's going on? I'm pretty new to Linux and Ubuntu.
So it looks like Miredo isn't running, yet I'm getting IPv6 addresses in eth0. It was that, I think, that a guy at Hurricane Electric was seeing and that caused him to see "6to4 tunneling - another automatic tunneling." Is that just a feature of Ubuntu?
He told me this:
"Look for a machine that has 6to4 tunneling configured and announcing 6to4 prefix to your linux box.
Here's the clue: According to your IPv6 route table, fe80::XXXX:XXXX:XXXX:XXXX is a link local address for your default gateway. Can you check and see which device has a MAC address of XX-XX-XX-XX-XX?"
It turns out that the device with that MAC address is my LinkSys router! (Which has NO IPv6 support!) I don't understand that.