Strange ipv6 6to4 experience

Hi,

I setup 6to4 on my machine, and I am having a very strange experience with it.

I have an ADSL modem called ppp0 - ipv4 works fine over it. I wanted to setup
6to4 tunnelling over it. Here's what I ended up with:

$ ip addr show
6: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,10000> mtu 1500 qdisc pfifo_fast qlen 3
link/ppp
inet XXX.XXX.XXX.XXX peer YYY.YYY.YYY.YYY/32 scope global ppp0
8: 6to4@NONE: <NOARP,UP,10000> mtu 1480 qdisc noqueue
link/sit XXX.XXX.XXX.XXX brd 0.0.0.0
inet6 2002:XXXX:XXXX::ff/16 scope global
valid_lft forever preferred_lft forever
inet6 ::XXX.XXX.XXX.XXX/128 scope global
valid_lft forever preferred_lft forever

$ ip -6 route
::/96 via :: dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh
1420 advmss 4294967295
2002:XXXX:XXXX::/64 dev eth0 metric 256 expires 21333029sec (null) 1500
ssthresh 1440 advmss 4294967295
2002::/16 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh 1420
advmss 4294967295
2000::/3 via ::192.88.99.1 dev 6to4 metric 16 expires 21326314sec (null)
1480 ssthresh 1420 advmss 4294967295
fe80::/64 dev eth0 metric 256 expires 21312355sec (null) 1500 ssthresh 1440
advmss 4294967295
fe80::/64 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh 1420
advmss 4294967295
ff00::/8 dev eth0 metric 256 expires 21312355sec (null) 1500 ssthresh 1440
advmss 4294967295
ff00::/8 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh 1420
advmss 4294967295

$ ip tunnel
sit0: ipv6/ip remote any local any ttl 64 nopmtudisc
6to4: ipv6/ip remote any local XXX.XXX.XXX.XXX ttl 255

$ ip link
6: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,10000> mtu 1500 qdis
link/ppp
8: 6to4@NONE: <NOARP,UP,10000> mtu 1480 qdisc noqueue
link/sit XXX.XXX.XXX.XXX brd 0.0.0.0


Static IPs blanked out for obvious reasons


Pinging any site (e.g. ftp.heanet.ie at 2001:770:18:aa40::c101:c140) does NOT
work. I have no firewall (for the sake of testing anyway).

I setup wireshark to capture on the ppp0 device while I used www.ipv6tools.com
to ping myself. I GOT ICMPv6 requests - but my machine sent out NO replies!

Then, I captured on the 6to4 device - I got NO requests, and NO replies!

What's going on? Please help me with this, I've been struggling with it for
many days now, with no solution to speak of.

Thanks

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Asfand Yar Qazi wrote:
> Hi,
>
> I setup 6to4 on my machine, and I am having a very strange experience
> with it.
>
> I have an ADSL modem called ppp0 - ipv4 works fine over it. I wanted to
> setup 6to4 tunnelling over it. Here's what I ended up with:
>
> $ ip addr show
> 6: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,10000> mtu 1500 qdisc
> pfifo_fast qlen 3
> link/ppp
> inet XXX.XXX.XXX.XXX peer YYY.YYY.YYY.YYY/32 scope global ppp0
> 8: 6to4@NONE: <NOARP,UP,10000> mtu 1480 qdisc noqueue
> link/sit XXX.XXX.XXX.XXX brd 0.0.0.0
> inet6 2002:XXXX:XXXX::ff/16 scope global
> valid_lft forever preferred_lft forever
> inet6 ::XXX.XXX.XXX.XXX/128 scope global
> valid_lft forever preferred_lft forever
>
> $ ip -6 route
> ::/96 via :: dev 6to4 metric 256 expires 21326314sec (null) 1480
> ssthresh 1420 advmss 4294967295
> 2002:XXXX:XXXX::/64 dev eth0 metric 256 expires 21333029sec (null)
> 1500 ssthresh 1440 advmss 4294967295
> 2002::/16 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh
> 1420 advmss 4294967295
> 2000::/3 via ::192.88.99.1 dev 6to4 metric 16 expires 21326314sec
> (null) 1480 ssthresh 1420 advmss 4294967295
> fe80::/64 dev eth0 metric 256 expires 21312355sec (null) 1500 ssthresh
> 1440 advmss 4294967295
> fe80::/64 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh
> 1420 advmss 4294967295
> ff00::/8 dev eth0 metric 256 expires 21312355sec (null) 1500 ssthresh
> 1440 advmss 4294967295
> ff00::/8 dev 6to4 metric 256 expires 21326314sec (null) 1480 ssthresh
> 1420 advmss 4294967295
>
> $ ip tunnel
> sit0: ipv6/ip remote any local any ttl 64 nopmtudisc
> 6to4: ipv6/ip remote any local XXX.XXX.XXX.XXX ttl 255
>
> $ ip link
> 6: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,10000> mtu 1500 qdis
> link/ppp
> 8: 6to4@NONE: <NOARP,UP,10000> mtu 1480 qdisc noqueue
> link/sit XXX.XXX.XXX.XXX brd 0.0.0.0
>
>
> Static IPs blanked out for obvious reasons
>
>
> Pinging any site (e.g. ftp.heanet.ie at 2001:770:18:aa40::c101:c140)
> does NOT work. I have no firewall (for the sake of testing anyway).
>
> I setup wireshark to capture on the ppp0 device while I used
> www.ipv6tools.com to ping myself. I GOT ICMPv6 requests - but my
> machine sent out NO replies!
>
> Then, I captured on the 6to4 device - I got NO requests, and NO replies!
>
> What's going on? Please help me with this, I've been struggling with it
> for many days now, with no solution to speak of.
>
> Thanks
>

And just to add some more info:

Accessing the www.ipv6tools.com site over ipv6 works! Firefox seems to use
ipv6 over ipv4 if it can. No other site I've tried works, but this does!

Also, pinging various 6to4 relays also works - e.g.
6to4.autotrans.consulintel.com, 6to4.ipv6.fh-regensburg.de. I can ping these
FINE.

Pinging normal sites (apart from www.ipv6tools.com) doesn't work.

--
To reply, take of all ZIGs !!

Alternative email address: (E-Mail Removed)IG