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

[Pekka Savola]

On Mon, 5 Mar 2001, Damien Miller wrote:

> On Mon, 5 Mar 2001, Pekka Savola wrote:
>
> > 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.
>
> It may be that the reason for the hack has been fixed. Can someone
> with a recent Linux kernel with IPv6 compiled in (or module loaded)
> build OpenSSH without the --with-ipv4-default hack and see whether
> it still waits ages for nameserver lookups at connect?

Is there some design reason why sshd couldn't bind to both address
families if specified to do so (non-default behaviour) even without
--with-ipv4-default.

Most people will probably want to use IPv4 by default.  But some would
enable IPv6 in packages as far as possible in case it doesn't hurt anyone
not using it.

-- 
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