FreeBSD does not reply to IPv6 Neighbor SolicitationsNUD

Victor Sudakov vas at sibptus.ru
Wed Jan 6 03:19:18 UTC 2021


Lutz Donnerhacke wrote:
> > $ ifconfig re1
> > re1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> >
> options=8209b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC,LI
> NKSTATE>
> >         ether c4:12:f5:33:c9:7c
> >         inet 192.168.170.5/24 broadcast 192.168.170.255
> >         inet6 fe80::c612:f5ff:fe33:c97c%re1/64 scopeid 0x2
> >         inet6 2001:470:ecba:3::5/64
> >         media: Ethernet autoselect (1000baseT <full-duplex>)
> >         status: active
> >         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
> 
> There is another possibility: The address could be in a tentative or
> duplicate state.
> In such a state the device SHOULD/MUST NOT respond to solicitation messages.
> 
> This can be caused by a "proxy arp/nd" device, which responds to an address
> in
> the local neighbour cache with its own solication message. It might be even
> a loop.
> We had such cases in the past, so that the device does not activate the IPv6
> address without disabling the NUD (was a windows server). For fixed
> addresses it
> should be save to disable the flag.
> 
> But this state should be reported by ifconfig.

I expect it should.

> 
> So, did you try the latest stable?

Not yet. 

When the situation occurs again, I'll turn on
net.inet6.icmp6.nd6_debug=0xff as Bjoern A. Zeeb has suggested, maybe
I'll see something useful. Then I'll think of updating the system.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
2:5005/49 at fidonet http://vas.tomsk.ru/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 455 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-net/attachments/20210106/6ab00070/attachment.sig>


More information about the freebsd-net mailing list