Help: IPv6 Problem

Hello,

I use ADSL to surf the web and Linux kernel is 2.4.21-47.EL by using RHEL
3. I have to access some IPv6 protocol based sites. I'm sure that I have
load the ipv6 module called "ipv6". But when I use ping6 command to have a
test it always shows following error messages.

PING xxx.xxx.xxx.xxx(cernet2.net) 56 data bytes
From ::1 icmp_seq=0 Destination unreachable: Address unreachable
From ::1 icmp_seq=1 Destination unreachable: Address unreachable
From ::1 icmp_seq=2 Destination unreachable: Address unreachable
From ::1 icmp_seq=3 Destination unreachable: Address unreachable
From ::1 icmp_seq=4 Destination unreachable: Address unreachable
From ::1 icmp_seq=5 Destination unreachable: Address unreachable
From ::1 icmp_seq=6 Destination unreachable: Address unreachable
From ::1 icmp_seq=7 Destination unreachable: Address unreachable
From ::1 icmp_seq=8 Destination unreachable: Address unreachable
From ::1 icmp_seq=9 Destination unreachable: Address unreachable
From ::1 icmp_seq=10 Destination unreachable: Address unreachable
From ::1 icmp_seq=11 Destination unreachable: Address unreachable
From ::1 icmp_seq=12 Destination unreachable: Address unreachable
From ::1 icmp_seq=13 Destination unreachable: Address unreachable
From ::1 icmp_seq=14 Destination unreachable: Address unreachable

Could you tell me how to fix that?

Thank you very much.

Amy

On 2008-09-13, Amy Lee <(E-Mail Removed)> wrote:
>
>
> Hello,
>
> I use ADSL to surf the web and Linux kernel is 2.4.21-47.EL by using RHEL
> 3. I have to access some IPv6 protocol based sites. I'm sure that I have
> load the ipv6 module called "ipv6". But when I use ping6 command to have a
> test it always shows following error messages.
>
> PING xxx.xxx.xxx.xxx(cernet2.net) 56 data bytes
> From ::1 icmp_seq=0 Destination unreachable: Address unreachable
> Could you tell me how to fix that?
>
> Thank you very much.
>
Do you have an entry for ::1 in /etc/hosts? The installer should have
put it there by default.

$ grep ::1 /etc/hosts
ff02::1 ip6-allnodes
::1 ip6-localhost ip6-loopback

And make sure that the output of "ifconfig lo" contains the line
inet6 addr: ::1/128 Scope:Host

Hello,

Bill Marcum a écrit :
> On 2008-09-13, Amy Lee <(E-Mail Removed)> wrote:
>>
>>I use ADSL to surf the web and Linux kernel is 2.4.21-47.EL by using RHEL
>>3. I have to access some IPv6 protocol based sites. I'm sure that I have
>>load the ipv6 module called "ipv6". But when I use ping6 command to have a
>>test it always shows following error messages.
>>
>>PING xxx.xxx.xxx.xxx(cernet2.net) 56 data bytes
>>From ::1 icmp_seq=0 Destination unreachable: Address unreachable
>>Could you tell me how to fix that?

Usually this message means that the neighbor discovery process for the
next hop failed. The next hop is the destination when it is directly
connected or the next router on the route otherwise.

Could you provide the output of the following commands ?
$ ip -6 addr
$ ip -6 route

> Do you have an entry for ::1 in /etc/hosts?

What for ?

> And make sure that the output of "ifconfig lo" contains the line
> inet6 addr: ::1/128 Scope:Host

I guess it does, else the OP would not get an error from ::1.

On Sat, 13 Sep 2008 21:39:42 +0200, Pascal Hambourg wrote:

> Hello,
>
> Bill Marcum a écrit :
>> On 2008-09-13, Amy Lee <(E-Mail Removed)> wrote:
>>>
>>>I use ADSL to surf the web and Linux kernel is 2.4.21-47.EL by using RHEL
>>>3. I have to access some IPv6 protocol based sites. I'm sure that I have
>>>load the ipv6 module called "ipv6". But when I use ping6 command to have a
>>>test it always shows following error messages.
>>>
>>>PING xxx.xxx.xxx.xxx(cernet2.net) 56 data bytes
>>>From ::1 icmp_seq=0 Destination unreachable: Address unreachable
>>>Could you tell me how to fix that?
>
> Usually this message means that the neighbor discovery process for the
> next hop failed. The next hop is the destination when it is directly
> connected or the next router on the route otherwise.
>
> Could you provide the output of the following commands ?
> $ ip -6 addr
> $ ip -6 route
>
>> Do you have an entry for ::1 in /etc/hosts?
>
> What for ?
>
>> And make sure that the output of "ifconfig lo" contains the line
>> inet6 addr: ::1/128 Scope:Host
>
> I guess it does, else the OP would not get an error from ::1.

It seems that I got nothing in /etc/hosts file. Shall I add
ff02::1 ip6-allnodes
::1 ip6-localhost ip6-loopback
into this file?

And the lo device does not contain the "inet6 addr: ::1/128 Scope:Host"
string.

ip -6 addr has nothing, and the output of "ip -6 route" is
172.16.200.1 dev ppp0 proto kernel scope link src 60.219.199.156
172.16.54.0/24 dev vmnet1 proto kernel scope link src 172.16.54.1
172.16.75.0/24 dev vmnet8 proto kernel scope link src 172.16.75.1
169.254.0.0/16 dev lo scope link
default via 172.16.200.1 dev ppp0

How to continue?

Thanks,

Amy

"Amy Lee" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> Hello,
>
> I use ADSL to surf the web and Linux kernel is 2.4.21-47.EL by using RHEL
> 3. I have to access some IPv6 protocol based sites. I'm sure that I have
> load the ipv6 module called "ipv6". But when I use ping6 command to have a
> test it always shows following error messages.
>
> PING xxx.xxx.xxx.xxx(cernet2.net) 56 data bytes
> From ::1 icmp_seq=0 Destination unreachable: Address unreachable
> From ::1 icmp_seq=1 Destination unreachable: Address unreachable
> From ::1 icmp_seq=2 Destination unreachable: Address unreachable
> ...
> From ::1 icmp_seq=14 Destination unreachable: Address unreachable
>
> Could you tell me how to fix that?
> Thank you very much.

Your routing table is empty.

D. Stussy a écrit :
> "Amy Lee" <(E-Mail Removed)> wrote in message
>>
>>From ::1 icmp_seq=0 Destination unreachable: Address unreachable
[...]
> Your routing table is empty.

I don't think so. The error message would be "Network is unreachable"
instead.

Amy Lee a écrit :
>
> It seems that I got nothing in /etc/hosts file. Shall I add
> ff02::1 ip6-allnodes
> ::1 ip6-localhost ip6-loopback
> into this file?

You can, but it is not necessary and won't help solving your problem.

> And the lo device does not contain the "inet6 addr: ::1/128 Scope:Host"
> string.

This is really surprising. What is the output of the following command ?
$ ping6 ::1

> ip -6 addr has nothing

What do you mean by nothing ? No output at all ? What is the output of
the following command ?
$ cat /proc/net/if_inet6

> and the output of "ip -6 route" is
> 172.16.200.1 dev ppp0 proto kernel scope link src 60.219.199.156
> 172.16.54.0/24 dev vmnet1 proto kernel scope link src 172.16.54.1
> 172.16.75.0/24 dev vmnet8 proto kernel scope link src 172.16.75.1
> 169.254.0.0/16 dev lo scope link
> default via 172.16.200.1 dev ppp0

This is the IPv4 routing table. You should not get that with -6 (or -f
inet6). What is the output of the following commands ?
$ route -n -A inet6
$ cat /proc/net/ipv6_route

PS : Linux 2.4.21 is very old and outdated (as well as RHEL 3, I guess).
You may consider upgrading, even to a more recent 2.4 kernel if you want
to stick to 2.4 series.