Subject: Re: How to identify 6to4 and 6in4 tunnels

From: zhuyj <[email-masked]>
Date: Tue, 28 Jan 2014 15:32:51 +0800

On 01/27/2014 08:59 PM, Nicolas Dichtel wrote:
> Le 27/01/2014 11:39, zhuyj a écrit :
>> Hi, Maintainers
>>
>> In our scene, we will create the 6in4/6to4 tunnel firstly and need to 
>> check the
>> tunnel type, secondly, we will configure the ip address on it. So, 
>> Could we have
>> any way to get the actual tunnel for 6in4 and 6to4 from current linux 
>> version?
>>
>> Both 6in4 and 6to4 have the same protocol “IPPROTO_IPV6” in Linux 
>> kernel. The
>> only difference is the ip address on the tunnel. Can we distinguish 
>> them in
>> Linux kernel?
> Just check the prefix, like it is done in check_6rd().
>
>
> Regards,
> Nicolas
>
Hi, Nicolas

Thanks for your reply. Maybe I can configure 6to4 tunnel by the 
following commands:

  ip tunnel add tun6to4 mode sit remote any local 1.202.252.122 ttl 64
  ip link set dev tun6to4 up
  ip -6 addr add 2002:01ca:fc7a::0012:0225:2122/128 dev tun6to4
  ip -6 route add 2000::/3 via ::192.88.99.1 dev tun6to4 metric 1

But the kernel can not identify the tunnel is 6to4 tunnel or 6in4 tunnel 
immediately. After the packets travel through this tunnel, the kernel 
can identify the type of the tunnel by check_6rd.

Is it right?

Best Regards!
Zhu Yanjun