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Obvious way (just setting up 6to4 tunnel and pinging) fails because ip command seems to be read-only on my VPS: can't change any networking-related settings.

So I try using raw sockets:

root@78.138.100.25#  printf '\x06\x00\x00\x00\x00\x40\x3a\x40''\x20\x02\x4e\x8a\x64\x19\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01''\x2a\x00\x14\x50\x40\x0c\x0c\x03\x00\x00\x00\x00\x00\x00\x00\x93''\x80\x00\x17\x21\x07\x71\x00\x01\xb7\x2e\x6b\x50\xbf\xd0\x07\x00\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37' | socat - ip-sendto:192.88.99.1:41 | hd

\x2a\x00\x14\x50\x40\x0c\x0c\x03\x00\x00\x00\x00\x00\x00\x00\x93 is ipv6.google.com
\x20\x02\x4e\x8a\x64\x19\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01 is 2002:78.138.100.25::1

tcpdump shows this:

18:31:26.982253 IP 78.138.100.25 > 192.88.99.1: IP6 2002:4e8a:6419::1 > 2a00:1450:400c:c03::93: ICMP6, echo request, seq 1, length 64

But no replies.

Am I doing everything correctly, but protocol 41 is filtered or there is mistake somewhere? Maybe there is some other user-space way to check if 6to4 is working?

share|improve this question
    
most likely you can't do many things on your VPS - it might be supporting very small subset of a 'real' kernel features. As for tunnels - why they should filter ipv4 traffic? – Serge Oct 2 '12 at 20:43
    
I don't know, just because... To prevent any unusual things. – Vi. Oct 2 '12 at 21:05

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