[Bug 221445] The absence of the accept_rtadv option causes an error "ping6: sendmsg: No buffer space available"

bugzilla-noreply at freebsd.org bugzilla-noreply at freebsd.org
Sat Aug 12 20:19:19 UTC 2017


https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221445

--- Comment #4 from Vladislav V. Prodan <admin at support.od.ua> ---
(In reply to Andrey V. Elsukov from comment #3)

>> Read the description of the bug again.
>> I described how I managed to get the ipv6 to work.

>It is wrong, and this is why it doesn't work.

It's someone who did not quite correctly implement the IPv6 implementation in
FreeBSD.
I can give a working example for Debian, there is the same crutch in the
destination route for the default router.

>> ifconfig_em0_ipv6="inet6 2001:41d0:e:XXX::1/128"

>What is the reason of /128 prefix length?

So decided marketers in the OVH. I already pointed out to them that there are a
number of vulnerabilities related to the substitution of IPv6 addresses.
Personally, I only need one ipv6 address.

>> ipv6_static_routes="ipv6gw"
>> ipv6_route_ipv6gw="-host 2001:41d0:000e:03ff:ff:ff:ff:ff -iface em0"

>This will not work on FreeBSD due to implementation specificity. 

Why not? It works the same.

# netstat -rn6
Routing tables

Internet6:
Destination                       Gateway                       Flags     Netif
Expire
::/96                             ::1                           UGRS        lo0
default                           fe80::12bd:18ff:fee5:ff80%em0 UG          em0
::1                               link#2                        UH          lo0
::ffff:0.0.0.0/96                 ::1                           UGRS        lo0
2001:41d0:e:XXX::/56              link#1                        U           em0
2001:41d0:e:XXX::1                link#1                        UHS         lo0
...
2001:41d0:e:3ff:ff:ff:ff:ff       00:22:4d:ad:ff:dc             UHS         em0
...
fe80::/10                         ::1                           UGRS        lo0
fe80::%em0/64                     link#1                        U           em0
fe80::222:4dff:fead:ffdc%em0      link#1                        UHS         lo0
fe80::%lo0/64                     link#2                        U           lo0
fe80::1%lo0                       link#2                        UHS         lo0
ff02::/16                         ::1                           UGRS        lo0


>When the kernel is going to send IPv6 packet, it does L2 lookup to determine L2 address. ND6 code does lookup for destination address only when an address is considered as neighbor. When you have not configured the correct prefix, the ND6 has not any interfaces where the destination address can be considered as neighbor. In your case even the L2 address of default router can not be found.

Honestly, I do not care how ND6 is implemented in FreeBSD.
I have issued a static IPv6 address with a given mask.
I have an IPv6 router address by default.
So what if he's not in the L2 segment? The network interface, where this Ipv6
is located, I know. Next, with these packages, the switches and routers of the
hoster will be sorted out.

I have a typical network scheme for many hosters dedicated servers.
I have a test machine with which I can work for a while to correct this
abnormal behavior.
If you have the time and the desire to eliminate this, in personal
correspondence I will provide access to the server.

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