latest openssh can not connect to older server

[Thomas Wolff]

Am 19.04.2020 um 14:31 schrieb Sharuzzaman Ahmat Raslan via Cygwin:
> Hi.
>
> New OpenSSH client will not connect to server that use SHA1.
>
> Please refer to this: https://www.openssh.com/legacy.html
>
> You should configure your old server to use more modern cipher
This isn't always a feasible approach. I access a WD MybookLive NAS 
storage via ssh. It still works with current openssh (8.2) but I 
wouldn't know how to find out the methods supported by my server and 
wouldn't like to risk the adventure to upgrade such a device. Therefore 
I'd suggest to configure in "legacy" methods in the cygwin openssh 
package as mentioned under the link above, to avoid such trouble.
Thomas

> Thank you
>
> On Sun, 19 Apr 2020, 8:13 pm David Balažic via Cygwin, <cygwin@cygwin.com>
> wrote:
>
>> Hi!
>>
>> I tried to backup some files from my server with scp and failed:
>>
>> $ scp  -v  root@the.server:/root/a.file  .
>> Executing: program /usr/bin/ssh host the.server, user root, command
>> scp -v -f /root/a.file
>> OpenSSH_8.2p1, OpenSSL 1.1.1f  31 Mar 2020
>> debug1: Connecting to the.server [192.168.1.11] port 22.
>> debug1: Connection established.
>> debug1: identity file /home/stein/.ssh/id_rsa type -1
>> debug1: identity file /home/stein/.ssh/id_rsa-cert type -1
>> debug1: identity file /home/stein/.ssh/id_dsa type -1
>> debug1: identity file /home/stein/.ssh/id_dsa-cert type -1
>> debug1: identity file /home/stein/.ssh/id_ecdsa type -1
>> debug1: identity file /home/stein/.ssh/id_ecdsa-cert type -1
>> debug1: identity file /home/stein/.ssh/id_ecdsa_sk type -1
>> debug1: identity file /home/stein/.ssh/id_ecdsa_sk-cert type -1
>> debug1: identity file /home/stein/.ssh/id_ed25519 type -1
>> debug1: identity file /home/stein/.ssh/id_ed25519-cert type -1
>> debug1: identity file /home/stein/.ssh/id_ed25519_sk type -1
>> debug1: identity file /home/stein/.ssh/id_ed25519_sk-cert type -1
>> debug1: identity file /home/stein/.ssh/id_xmss type -1
>> debug1: identity file /home/stein/.ssh/id_xmss-cert type -1
>> debug1: Local version string SSH-2.0-OpenSSH_8.2
>> debug1: Remote protocol version 2.0, remote software version
>> dropbear_2011.54
>> debug1: no match: dropbear_2011.54
>> debug1: Authenticating to the.server:22 as 'root'
>> debug1: SSH2_MSG_KEXINIT sent
>> debug1: SSH2_MSG_KEXINIT received
>> debug1: kex: algorithm: (no match)
>> Unable to negotiate with 192.168.1.11 port 22: no matching key
>> exchange method found. Their offer:
>> diffie-hellman-group1-sha1,diffie-hellman-group14-sha1
>>
>>
>> I tried OpenSSH_8.0p1-2 which is still available in the cygwin
>> setup-x86_64.exe wizard and that version works fine.
>> (the version above is 8.2.p1-1 in the setup wizard)
>>
>> Regards,
>> David
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