--with-ipv4-default and sshd IPv4/6 dual bind hack

[Pekka Savola]

Hello all,

I just found a bug a nice bug that can be turned into a real feature on
systems (usually Linux) that are built with --with-ipv4-default.

If you enable IPv6 in kernel, and enable both listenaddress 0.0.0.0 and
::, sshd will error out 'address family not supported'.

However, you can work around this error by starting sshd with 'sshd -4 -6'.

As far as man page is concerned, I'm getting the impression that you
should be able to use only  -4 or -6, not both.

-- 
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