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Re: [Curdle] draft-ietf-curdle-ssh-kex-sha2 and diffie-hellman-group1-sha1 (1024-bit DH)

Damien Miller <djm@mindrot.org> Fri, 21 July 2017 04:15 UTC

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Date: Fri, 21 Jul 2017 14:14:27 +1000
From: Damien Miller <djm@mindrot.org>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>
cc: "curdle@ietf.org" <curdle@ietf.org>, "Mark D. Baushke" <mdb@juniper.net>
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Subject: Re: [Curdle] draft-ietf-curdle-ssh-kex-sha2 and diffie-hellman-group1-sha1 (1024-bit DH)
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On Fri, 20 Jul 2017, Peter Gutmann wrote:

> Damien Miller <djm@mindrot.org> writes:
> 
> >On Thu, 20 Jul 2017, Peter Gutmann wrote:
> >
> >> That assumes OpenSSH is the client.  When I run into it it's always the
> >> server, so there's no error message or other information available.
> >
> >Isn't it the client's job to generate a useful error then?
> 
> What error message could the client display?  All it knows is that the remote
> server claims to be OpenSSH, and it shut down the connection after getting the
> client hello.  At which point you're back to trial-and-error with the server
> admin to try and get them to figure out a config that works.

The server doesn't shut down the connection before sending its own KEXINIT
that includes the set of supported algorithms.

-d

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