Wow. I am stunned. This has solved the problem. I have spent more than a day
searching for such a solution.
I am now able to log into a Ubuntu 16.04 LTS server with OpenSSH 7.2
Client is a fresh install of FreeDOS 1.2 where I installed ssh2dos with "FDNPKG
install ssh2dos"
Thank you very, very much!
Ulrich
> Am 27.01.2017 um 06:39 schrieb Dan Schmidt <helpdesk...@gmail.com>:
>
> I forgot - you may need to regenerate your keys with "ssh-keygen -A" after
> modifying the server.
>
> On Thu, Jan 26, 2017 at 10:38 PM, Dan Schmidt <helpdesk...@gmail.com
> <mailto:helpdesk...@gmail.com>> wrote:
> I am unsure what it is that makes ssh2dos so unstable for me - nobody else
> has this issue?
>
> I would like to answer Ulrich on how he can modify his Ubuntu server, but
> first, a warning: These algorithms were disabled because they are obsolete
> and insecure. Using a token based login, such as google-authenticator, may
> be advisable if your server is public facing.
>
> Firstly, add this to your server's /etc/ssh/sshd_config:
>
> KexAlgorithms diffie-hellman-group1-sha1,curve25519-sha...@libssh.org
> <mailto:curve25519-sha...@libssh.org>,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
> Ciphers 3des-cbc,blowfish-cbc,aes128-cbc,aes128-ctr,aes256-ctr
> HostKeyAlgorithms +ssh-dss
>
> Then, make use of the -g option - it goes BEFORE your username in ssh2dos.
> You should now be able to connect.
>
> I do not know why simply adding +diffie-hellman-group1-sha1 doesn't work, it
> seems it should. Also, I was in a rush - I may be excluding some newer
> options - report back if you find/add them with success.
>
> -Dan
>
> On Thu, Jan 26, 2017 at 9:42 PM, Karen Lewellen <klewel...@shellworld.net
> <mailto:klewel...@shellworld.net>> wrote:
> Hi Bill,
> While I appreciate your desire for wisdom, I feel rather sure my specific
> situation will not apply to anyone else here most likely.
> I use ssh2d386 to access at least one commercial shell, but those shell
> services are maintained by others. I am not for example accessing my own
> server.
> If the servers you desire reaching are run by other people, give me an
> example and I will try.
> If my many years of computing has taught me anything is that the word
> Personal is important for a reason.
> Kare
>
>
>
> On Thu, 26 Jan 2017, William Dudley wrote:
>
> Karen,
>
> If you know how to get ssh2d386 to connect to a modern openssh, as on
> Ubuntu 16.04,
> please share the recipe with us!
>
> Thanks,
> Bill Dudley
>
>
> This email is free of malware because I run Linux.
>
> On Thu, Jan 26, 2017 at 9:10 PM, Karen Lewellen <klewel...@shellworld.net
> <mailto:klewel...@shellworld.net>>
> wrote:
>
> Well, if you have given up no point in my sharing.
> We use the same edition of Ubuntu, both with dreamhost who has my office,
> and here at shellworld.
> While the latter requires me to make use of a few ssh2021b options, the -g
> option for example, I encounter no issues.
> I am going to guess that things like machine speed, mine is a p3 with
> allot of memory, impacts your situation.
> nor, I would hope, your location in the world.
> Sorry I did not notice your post before you abandoned the effort.
> Kare
>
>
>
> On Fri, 27 Jan 2017, Ulrich Hansen wrote:
>
>
> Am 26.01.2017 um 18:19 schrieb Karen Lewellen <klewel...@shellworld.net
> <mailto:klewel...@shellworld.net>>:
>
> As I am presently writing this e-mail using ssh2d386 from the ssh2dos
> package ssh2021b, perhaps I can help you troubleshoot.
>
>
> Hi Karen!
>
> I am using the exact same program and version.
>
> for the record, I am not using freedos, but the ms dos 7.10 package
> mentioned on this list.
> Still every day several times a day I connect to two different servers
> using this package.
>
>
> I guess your servers still run OpenSSH in versions earlier than 6.9.
>
> may I ask again what your issue is presently?
>
>
> Actually I have given up on it. I spent another day trying to get it to
> work, but without success.
>
> The problem is that I can’t connect to an Ubuntu 16.04 LTS server with
> OpenSSH 7.2.
>
> SSH2D386 gives the message:
>
> Expected KEX_DH_GEX_GROUP
> DH key exchange failed
>
> The server logs:
> Jan 27 00:02:22 ubuntu-VirtualBox sshd[2651]: error: kex protocol
> error: type 30 seq 1 [preauth]
> Jan 27 00:02:22 ubuntu-VirtualBox sshd[2651]: error: Received
> disconnect from 192.168.1.110 port 645:3: Expected KEX_DH_GEX_GRO
>
> As I wrote I already had problems connecting to a Debian 8 server with
> OpenSSH 6.7.
> But there I could fix it with these lines in /etc/ssh/sshd_config on the
> server.
>
> Ciphers aes128-cbc
> KexAlgorithms diffie-hellman-group-exchange-sha1
> MACs hmac-sha1
> HostKeyAlgorithms ssh-css
>
> But in OpenSSH 7.2 this didn’t work.
>
> What else did I try?
>
> I tried to set MTU=576 in C:\FDOS\WATTCP.CFG.
>
> I tried to recompile OpenSSH.
> The first time with adding this line in in compat.c:
> { "SSHDOS*", SSH_OLD_DHGEX },
> The second time with this one:
> { "SSHDOS*", SSH_BUG_NOREKEY|SSH_BUG_FIRSTKEX },
>
> Both were not able to let SSH2D386 connect. It worked great with other
> SSH clients.
>
> The idea was that SSH2DOS uses code from PuTTY and there were already
> several exceptions in combat.c for old PuTTY versions. The reason seems to
> be that OpenSSH implemented RFC4419 and old PuTTY versions and SSH2DOS did
> not. See [1], [2].
>
> I even looked at the SSH2DOS source code. But I have no experience with
> OpenWatcom. I installed it but gave up, when I saw I also had to compile
> the WATT32 TCP/IP stack.
>
> SSH2DOS uses PuTTY code, which is also Free Software. So in theory it
> should be possible to replace the old PuTTY code with a more recent one.
>
> cheers
> Ulrich
>
>
> [1] https://forums.red-gate.com/viewtopic.php?f=198&t=78958
> <https://forums.red-gate.com/viewtopic.php?f=198&t=78958>
> [2] http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/
> <http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/>
> rfc4419.html
>
>
>
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