ipv6 problem
Thomas Sandford
freebsduser at paradisegreen.co.uk
Thu Feb 3 16:10:23 UTC 2011
On 01/02/2011 07:29, pepe wrote:
> I have 2001:14b8:10:402::/64 ipv6 from my isp and I cant get it working.
> Ifconfig should be ok:
> backup# ifconfig rl0 inet6
>
> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> options=8<VLAN_MTU>
> inet6 2001:14b8:10:402:2::1 prefixlen 64
Looks a bit odd - I would expect to see a link-local address too - eg
%ifconfig bge0 inet6
bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=8009b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,LINKSTATE>
inet6 fe80::20b:cdff:fef2:9a57%bge0 prefixlen 64 scopeid 0x1
inet6 2001:8b0:cae3:1:20b:cdff:fef2:9a57 prefixlen 64 autoconf
> default gateway is set to 2001:14b8:10:402:1::1.
That sounds a slightly odd comment, since in general IPv6 routing is
done with auto-discovery. Especially given the fact that the default
route quoted lies within the same subnet (2001:14b8:10:402:: prefixlen
64) as the host in question.
When I try to traceroute
> irc server for example
> I get this:
>
> traceroute6: Warning: irc.cc.tut.fi has multiple addresses; using
> 2001:708:310:4952:4320:5365:7276:6572
I get this message too - because the host irc.cc.tut.fi DOES have
multiple addresses:
%dig irc.cc.tut.fi aaaa
; <<>> DiG 9.6.2-P2 <<>> irc.cc.tut.fi aaaa
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24710
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 3, ADDITIONAL: 0
;; QUESTION SECTION:
;irc.cc.tut.fi. IN AAAA
;; ANSWER SECTION:
irc.cc.tut.fi. 3134 IN AAAA
2001:708:310:4952:4320:5365:7276:6572
irc.cc.tut.fi. 3134 IN AAAA
2001:708:310:4952:4320:436c:6965:6e74
;; AUTHORITY SECTION:
cc.tut.fi. 172334 IN NS ns-secondary.funet.fi.
cc.tut.fi. 172334 IN NS kaustinen.cc.tut.fi.
cc.tut.fi. 172334 IN NS ressu.cc.tut.fi.
;; Query time: 0 msec
;; SERVER: 81.187.228.6#53(81.187.228.6)
;; WHEN: Thu Feb 3 15:34:06 2011
;; MSG SIZE rcvd: 164
> traceroute6 to irc.cc.tut.fi (2001:708:310:4952:4320:5365:7276:6572) from
> 2001:14b8:10:402:2::1, 64 hops max, 12 byte packets
> 1 2001:14b8:10:402:2::1 2026.908 ms !A 2999.587 ms !A 3000.423 ms !A
From the traceroute6 manpage
!A Destination Unreachable - Address Unreachable.
It also appears that your first hop address is the same as your source
address, which does suggest that routing is more than a little bit screwy.
On my system I get:
%traceroute6 -n irc.cc.tut.fi
traceroute6: Warning: irc.cc.tut.fi has multiple addresses; using
2001:708:310:4952:4320:436c:6965:6e74
traceroute6 to irc.cc.tut.fi (2001:708:310:4952:4320:436c:6965:6e74)
from 2001:8b0:cae3:1:20b:cdff:fef2:9a57, 64 hops max, 12 byte packets
1 2001:8b0:cae3:1:21a:a2ff:fe34:e50b 1.349 ms 0.969 ms 1.011 ms
2 2001:8b0:0:53:203:97ff:fe05:8000 129.118 ms 143.449 ms 119.622 ms
3 2001:7f8:4::50e8:1 132.075 ms 119.009 ms 117.983 ms
4 2001:7f8:4::1b1b:1 123.832 ms 114.424 ms 119.675 ms
5 2001:7f8:4::a2b:1 114.905 ms 119.009 ms 118.030 ms
6 2001:948:1:8::3 134.205 ms 143.579 ms 130.875 ms
7 2001:948:1:2::3 145.068 ms 145.049 ms 156.321 ms
8 2001:948:3:2::3 165.258 ms 171.228 ms 156.591 ms
9 2001:708:0:f000:0:60:3060:2 233.114 ms 163.319 ms 158.668 ms
10 2001:708:310::2 67.252 ms 58.513 ms 59.656 ms
11 2001:708:310:4952:4320:436c:6965:6e74 58.906 ms 58.310 ms 58.045 ms
(I ran it with -n as I think in this case the raw IPv6 addresses are
more informative than the rDNS lookups).
> So. Could this be problem in my configs or is this because of something
> wrong at the isp side?
It does look as though there is something a little odd with your
configs. It's difficult to be more specific because you've given very
little information.
If things at the router (whether yours or at the isp) are set up
correctly then the single line in /etc/rc.conf
ipv6_enable="YES"
should be sufficient to autoconfigure BOTH ipv6 address and routing
using Router Discovery. This is all that I had to do on the machine I
generated the above config dumps & traces from.
In my case my ISP (AAISP in the UK) have allocated me a /48 2001:8b0:cae3::
Traffic comes to me over a 6to4 tunnel from the ISP terminated on a
Cisco router (though I tested it on a FreeBSD host before I got the 6to4
tunnel set up on the router). The LAN side interface of the router has
Router Advertisements enabled which means that the above rc.conf line is
all that is required for everything to "just work".
--
Thomas Sandford
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