Re: Debian and IPV6

[Mark Zimmerman <mark@foresthaven.com>]

On Sun, Dec 29, 2002 at 09:41:49AM -0600, Russ Cook wrote:
> Mark,
>   Thanks for the reply.  I tried your suggestion of adding the -- -6
> option to the start-stop-daemon lines in /etc/init.d/ssh.  I then
> tried to connect to the host with ssh and ssh -6.  Both attempts succeded,
> as shown in the subsequent netstat -A inet6 -an
> 
> Script started on Sun Dec 29 09:38:04 2002
> p90:/home/russ# netstat -A inet6 -an
> Active Internet connections (servers and established)
> Proto Recv-Q Send-Q Local Address           Foreign Address         State
> tcp        0      0 :::80                   :::*                    LISTEN
> tcp        0      0 :::22                   :::*                    LISTEN
> tcp        0      0 ::ffff:192.168.1.1:22   ::ffff:192.168.1.2:3238 ESTABLISHED
> tcp        0      0 3ffe:b80:1853:1:250::22 3ffe:b80:1853:1:25:3239 ESTABLISHED
> p90:/home/russ# exit
> 
> Script done on Sun Dec 29 09:38:19 2002
> 
> It represents my IPv4 connection with a IPv6 style address, however.
> Does this imply that both connections are actually ip6 connections?
> 

Yes. Addresses like this are a feature of IPv6. I suspect what is
happening is this:

1. ssh tries to connect with IPv4 and fails because the server is not
   listening on that port.
2. ssh builds the hybrid address, tries that, and succeeds.

To verify that sshd is not listening on IPv4, substitute inet for
inet6 in your netstat command and look for port 22.

> Would you mind sending me the sample lines from your sshd_config file
> where you configured two listening lines with explicit addresses?
> 

ListenAddress 192.168.132.16
ListenAddress fec0::a00:20ff:fe0c:81ca

-- Mark