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Re: Haven't seen this ssh output before



Harry Putnam <reader@newsguy.com> writes:

> I'm not at all clear on how one would go about making an adjustment in
> sshd_config to allow the algs used by my REMOTE-sol to be recognized.
>
> REMOTE-sol does not appear to be using OpenSSH .. maybe a solaris
> version of SSH.  
>
> In light of the comments above; if you have any more info on this and
> have the time... please post.

I managed to get a bit of a solution after careful study of the error
output and man sshd_config (Largely from being guided by your post)

It shows the default kex algorithems and the possible kex alg.

I thought of just adding one that matched the list of my clients
available  choices to sshd_config on REMOTE-deb like so:

 
  KexAlgorithms  diffie-hellman-group-exchange-sha1

Then restart sshd.

That works, but I was afraid that might mean the defaults would be
dropped and only `diffie-hellman-group-exchange-sha1' would be
offered.  I was afraid that might cause failure on some other hosts.

It was not clear to me from `man sshd_config' just how exactly to do
this.

I finally opted for listing all the defaults +
 diffie-hellman-group-exchange-sha1

Like this (in REMOTE-deb /etc/ssh/sshd_config):

   KexAlgorithms   curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1

That also works.  

Now, since debian chose to follow the new upstream sshd defaults and
limits due to `UNSAFE' alg.  I'm wondering if by adding one of those
discarded algs back in there... I may be creating a security hole.

The REMOTE-deb host is exposed to ssh via the internet... not just
through the lan.

Any opinions on what I may have created?


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