Forum - using 6in4 and aiccu -> creates 4 different "local" addresses ? :: SixXS

using 6in4 and aiccu -> creates 4 different "local" addresses ?

Shadow Hawkins on Sunday, 08 May 2011 17:07:42

Tag [/code] is not closed

using 6in4 and aiccu -> creates 4 different "local" addresses ?

Jeroen Massar SixXS Staff

on Sunday, 08 May 2011 17:55:55

Those local addresses are the IPv6 representations of your IPv4 addresses. fe80::c0a8:6401 => c0a8:6401 => 0xc0.0xa8.0x64.0x01 $ printf "%d.%d.%d.%d\n" 0xc0 0xa8 0x64 0x01 192.168.100.1 Apparently you have 4 different IPv4 addresses on that machine. As the 'sit' tunneling does not know what the local address is, it derives the link-local address based on all four of them. It is fe80::/10 btw, which is the link-local address range. The f0f5 version is your global IPv4 address: $ printf "%d %d %d %d\n" 0x50 0x5f 0xfa 0x9c 80 95 250 156 As such, we have just learned you have three internal IPv4 addresses and one global one and x'ing out the IPv4 addresses didn't help, especially as whois on the IPv6 address will also show that one ;) (and yes, I am lazy, not going to do hex in my head even if I can, it is Sunday ;)

using 6in4 and aiccu -> creates 4 different "local" addresses ?

Shadow Hawkins on Sunday, 08 May 2011 19:18:44

I had a feeling it would be noobish to x'ing IPv4 (whois came to my mind, but not the others), but I am noob, so I am not ashamed ;-). You are right, I have in general 4 IPv4 addresses, one external, one for openvpn tunnel, and two for two local ranges on different interfaces, so there is definitely a point in what you say. But each one is on different interface (even though openvpn tunnel is not physical interface). I do not understand why aiccu needs all of them. I thought each interface should get one "local" IPv6 address, and forwarding between them will be set up by route. At least it is what is happening on other interfaces, where each has one "local" IPv6, and eventually, if assigned by other means, also one "global" IPv6. But I am just coming from IPv4 and do not know IPv6 much (at all). Anyway, thanks for the answer, it seems I still have something to digest, and you pointed me in the right direction :).

using 6in4 and aiccu -> creates 4 different "local" addresses ?

Jeroen Massar SixXS Staff

on Sunday, 08 May 2011 23:09:27

I do not understand why aiccu needs all of them.

AICCU has not directly much to do with it. It is the implementation of the 'sit' device in the Linux kernel that does this. It needs to generate a link-local address (the fe80::/10 ones) and to do that it uses unique addresses, which it thus takes from the possible parent interfaces.

I thought each interface should get one "local" IPv6 address, and forwarding

between them will be set up by route.

In IPv6 every interface can have effectively unlimited addresses, thus also local ones.

At least it is what is happening on other interfaces, where each has one

"local" IPv6, and eventually, if assigned by other means, also one "global"

IPv6. But I am just coming from IPv4 and do not know IPv6 much (at all).

For normal (read: ethernet) interfaces the link-local is derived from the MAC address, as that is the layer above it. In the case of a sit-device, the layer above it is the IPv4 layer, as such it derives the link-local address from that. You don't have to worry about any of these little details though, unless you are going to firewall things off, but then again, firewalling is a tricky thing to get right anyway.

using 6in4 and aiccu -> creates 4 different "local" addresses ?

Shadow Hawkins on Monday, 09 May 2011 01:13:54

Thanks again for the explanation :).

Please note Posting is only allowed when you are logged in.