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Date:      Wed, 11 Sep 2013 10:16:21 -0600
From:      Ian Lepore <ian@FreeBSD.org>
To:        Dag-Erling =?ISO-8859-1?Q?Sm=F8rgrav?= <des@des.no>
Cc:        current@FreeBSD.org
Subject:   Re: HEADS UP: OpenSSH with DNSSEC support in 10
Message-ID:  <1378916181.1111.617.camel@revolution.hippie.lan>
In-Reply-To: <86d2ofe556.fsf@nine.des.no>
References:  <86hadre740.fsf@nine.des.no> <1378913151.1111.613.camel@revolution.hippie.lan> <86d2ofe556.fsf@nine.des.no>

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On Wed, 2013-09-11 at 17:42 +0200, Dag-Erling Sm=F8rgrav wrote:
> Ian Lepore <ian@FreeBSD.org> writes:
> > So what happens when there is no dns server to consult?  Will every
> > ssh connection have to wait for a long dns query timeout?  What if th=
e
> > machine is configured to use only /etc/hosts?
>=20
> If there is no DNS server, no query will be sent.
>=20
> > What if a DNS server is configured but doesn't respond?
>=20
> The DNS request will time out.
>=20
> In the vast majority of cases, you will either have no DNS at all (so n=
o
> query will be sent), or you will have a functioning DNS server.  In a
> slightly less vast majority of cases, you will not be able to resolve
> the server's IP address without DNS anyway.
>=20
> > For that matter, I just realized I'm a bit unclear on who is querying
> > DNS for this info, the ssh client or the sshd?
>=20
> The client - and you can override this in your ~/.ssh/config or on the
> command line (-oVerifyHostKeyDNS=3Dno).
>=20
> DES
> --=20

Thanks.  If this is client-side I'm much less scared by it.  At $work we
have embedded systems with less than full network functionality, often
including either /etc/hosts usage or worse, sometimes a dns is
configured but unreachable, and we ssh into them a lot for development.

-- Ian





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