IPv6 neighbor solicitation -> no response

IPv6 neighbor solicitation -> no response

[Jan Oravec]

Hi,


After upgrade from 2.2 to 2.4 kernel machine stopped answering IPv6 neighbor solicitation requests on pointtopoint interfaces.

Response from machine running 2.2 kernel:

14:50:05.762924 fe80::201:2ff:fe0f:b5a2 > fe80::3e8c:1d09: icmp6: neighbor sol: who has fe80::3e8c:1d09
14:50:05.810325 fe80::3e8c:1d09 > fe80::201:2ff:fe0f:b5a2: icmp6: neighbor adv: tgt is fe80::3e8c:1d09

After upgrade to 2.4 kernel, I do not receive any answer from fe80::3e8c:1d09. Routing, etc. works without it perfectly, but for example OSPF6 daemon does not.


Best Regards,

-- 
Jan Oravec<wsx@wsx6.net> PGP:www.wsx6.net/pgp-key.txt IRC:WSX
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Re: IPv6 neighbor solicitation -> no response

[Jan Oravec]

> > After upgrade from 2.2 to 2.4 kernel machine stopped answering IPv6 neighbor solicitation requests on pointtopoint interfaces.
> 
> What kind of pointopont interface?
sit tunnel (IPv6 over IPv4)
> 
> > 14:50:05.762924 fe80::201:2ff:fe0f:b5a2 > fe80::3e8c:1d09: icmp6: neighbor sol: who has fe80::3e8c:1d09
> 
> Are you sure that machine really has this address: fe80::3e8c:1d09?
Yes, I am sure, because I am receiving packets from fe80::3e8c:1d09 thru this tunnel...


Here is the example (another Linux (2.4.8), so address isn't fe80::3e8c:1d09):
$ /sbin/ifconfig sit1
sit1      Link encap:IPv6-in-IPv4
          inet6 addr: fe80::c348:987/10 Scope:Link
          inet6 addr: 3ffe:80e8:2::2/64 Scope:Global
          inet6 addr: fe80::a00:1/10 Scope:Link
          inet6 addr: fe80::c0a8:6401/10 Scope:Link
          UP POINTOPOINT RUNNING NOARP  MTU:1480  Metric:1
          RX packets:6050 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6097 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1083250 (1.0 Mb)  TX bytes:629382 (614.6 Kb)

(server has multiple network cards, so it has multiple link-local addresses)

When I am trying to send packets there (from another side of tunnel):
11:13:45.520765 fe80::201:2ff:fe0f:b5a2 > fe80::c348:987: icmp6: neighbor sol: who has fe80::c348:987
11:13:46.520777 fe80::201:2ff:fe0f:b5a2 > fe80::c348:987: icmp6: neighbor sol: who has fe80::c348:987
11:13:47.520796 fe80::201:2ff:fe0f:b5a2 > fe80::c348:987: icmp6: neighbor sol: who has fe80::c348:987

packets arrive OK, I get answer from fe80::c348:987, but I don't receive answer from neighbor solicitation.
other OS I tried (FreeBSD, Linux 2.2) are answering correctly:

11:21:41.527954 fe80::201:2ff:fe0f:b5a2 > fe80::201:2ff:fea8:2f55: icmp6: neighbor sol: who has fe80::201:2ff:fea8:2f55
11:21:41.541748 fe80::201:2ff:fea8:2f55 > fe80::201:2ff:fe0f:b5a2: icmp6: neighbor adv: tgt is fe80::201:2ff:fea8:2f55


Regards,

Jan