IPV6 problem : nd6_lookup: failed to add route for a neighbor

[Steve Bertrand]

Tuc at T-B-O-H.NET wrote:
> Hi,
> 
> 	Running 5.5 (And no "upgrade" messages please, I'm forced to, its
> out of my hands) and trying to bring up HE's IPV6.
> 
> 	I've got it running on a 4.10 system (Ok, feel free to tell me
> to upgrade, this one is more a lazy issue.. But I am making progress. I
> bought new drives that'll be here next week so I can load 7.0 from
> scratch) with no worries at all. Piece of cake, has been for ages.
> 
> 	But once I brought it all up, I got :
> 
> kernel: nd6_lookup: failed to add route for a neighbor(2001:0470:0007:0028::0001), errno=17
> 
> 	and ALOT of them. Taking a quick look in Google, it seems that they claim
> its a prefix len issue, but I am running with a 128 prefix length even though it seems
> they say :
> 
> Client IPv6 address:  	2001:470:7:28::2/64
> 
> The script they suggest, and I used, is :
> 
> ifconfig gif0 create
> ifconfig gif0 tunnel MYIP 216.66.22.2
> ifconfig gif0 inet6 2001:470:7:28::2 2001:470:7:28::1 prefixlen 128
> route -n add -inet6 default 2001:470:7:28::1
> ifconfig gif0 up
> 
> 	The tunnel came up, was passing traffic, but those messages were
> getting out of hand. I tried a prefixlen of 64, and I got:

...hmmmm. I'm not certain here, but since /128 represents only a single 
address, I can understand why FreeBSD is getting confused. A /128 is an 
IP within its own solitary subnet, so I'd have to guess that you need a 
route to the remote end of the tunnel before you can set it as a default 
gateway.

I've been needing to set up a few more tunnels, so I'll try one with 
FreeBSD this morning with the same setup you have to try to replicate 
the problem (on 7.0).

> 	ifconfig: ioctl (SIOCAIFADDR): Invalid argument

What was the command that you had entered when you received the above 
error? When you tried to change prefix length, did you destroy the 
existing tunnel first?

> Sendmail seemed a bit cranky :
> 
> Jun 26 23:53:19 MYHOST sendmail[17543]: gethostbyaddr(IPv6:2001:470:7:28::2) failed: 1

I believe this is a reverse DNS issue. From how I perceive that message, 
Sendmail is trying to retrieve a hostname based on that IP.

Steve