[Bug 164] X-forwarding when connecting to an IPv6-enabled host doesn't work.

[Pekka Savola]

On Mon, 28 Oct 2002, Colin Watson wrote:
> In article <Pine.LNX.4.44.0210281202420.30858-100000 at netcore.fi>
> on openssh-unix-dev, Pekka Savola wrote:
> >In any case, I'd like to see demonstrated failures.
> >
> >SSH over IPv6 + X-forwarding works just fine for me...
> 
> The two we've had reported (and which I can reproduce here) are:
> 
>   http://bugs.debian.org/152545
>   http://bugs.debian.org/153154

Clarification: do these happen also if you run plain sshd, not 'sshd -6'?  
The latter has some problems..

> In brief, $DISPLAY is set to 'localhost:10.0' but ssh binds to ::1:6010;
> ::1 is ip6-localhost here, not localhost. Even if I did have an X11 over
> IPv6 implementation, the incorrect $DISPLAY would prevent it being used.
> 
> Perhaps it could be configurable whether X11 forwarding uses IPv6.
> 
>   $ uname -a
>   Linux eurydice 2.4.20-pre10 #1 Fri Oct 11 19:25:05 BST 2002 i686 AMD Duron(tm) Processor  AuthenticAMD GNU/Linux
>   $ ssh -6 -X ::1
>   colinw@::1's password:

Does this problem also occur if you don't use '-6'?  Probably not.

>   $ ping6 localhost
>   unknown host
>   $ ping6 ip6-localhost
>   PING ip6-localhost(ip6-localhost) 56 data bytes
>   64 bytes from ip6-localhost: icmp_seq=1 ttl=64 time=0.056 ms
> 
>   [...]
> 
>   $ netstat -an | grep 6010
>   tcp        0      0 ::1:6010                :::*                    LISTEN
>   $ xterm
>   xterm Xt error: Can't open display: localhost:10.0
>   $ DISPLAY=ip6-localhost:10.0 xterm
>   _X11TransSocketINETConnect: Can't get address for ip6-localhost
>   xterm Xt error: Can't open display: ip6-localhost:10.0

I can't reproduce your problem on RHL73:

--8<--
[psavola at haukka psavola]$ ssh sampo.ipv6
Last login: Mon Oct 28 14:06:22 2002 from haukka.ipv6.csc.fi
msgs: Command not found.
Terminal type is xterm
sampo2 ~> echo $DISPLAY
localhost:13.0
sampo2 ~> grep ::1 /etc/hosts
::1			ip6-localhost.localdomain	ip6-localhost
sampo2 ~> xterm
sampo2 ~> 
--8<--

Note: by default, there is no entry for ::1 in hosts, I added one to try 
to test the problem.

In conclusion, I believe there are some variables (possibly ones mentioned 
above) which make this problematic for some but not others.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords