SSH - authentication failed Disconnected; no more authentication methods available

[Paolo_c]

I was having issues with using SSH so generated a new host key (using the default options under tcpip$config.com option 3 ..... ) under the system account to see if that would resolve the issue. Following this if i now try and SSH to the server from other VMS hosts I can connect/login, but note the following message is displayed  

EGLIVE>ssh system@ukdcaipf04
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the host key has just been changed.
Please contact your system administrator.
Add correct host key to "ssh2/hostkeys/key_22_ukdcaipf04.pub"
to get rid of this message.
(or remove the keyfile, and connect again.)

Received server key's fingerprint:

xekal-bugek-koryp-bylif-sines-fydov-sybuh-kosuc-nyhip-pecat-raxyx

You can get a public key's fingerprint by running

$ ssh_keygen "-F" publickey.pub

on the keyfile.

Agent forwarding is disabled to avoid attacks by corrupted servers.

X11 forwarding is disabled to avoid attacks by corrupted servers.

SYSTEM's password:

Authentication successful.

Last interactive login on Tuesday, 1-DEC-2020 07:57:19.35
Last non-interactive login on Tuesday, 1-DEC-2020 08:07:17.42

Also if i try and SSH from the local server to other VMS or Unix hosts it errors out with the following 

KIFI02_VSI842L1>>>ssh system@eglive

@@KF$COMMON:[SYSMGR]ANNOUNCE.TX

warning: Authentication failed.
Disconnected; no more authentication methods available (No further authenticatio
n methods available.).

KIFI02_VSI842L1>>>

Could you please advise what steps i need to resolve the above. thanks.

P.S i recently upgraded this Server from HP 8.4-2 to VSI 8.4-2l1 (and following the upgrade was able to ssh into and out of the Server without any issue so not sure what happended in the intervening period to cause the outbound issue with SSH. 

 KIFI02_VSI842L1>>>ssh -vvv 'localhost'
$1$DGA3021:[SYS0.SYSCOMMON.][SYSEXE]TCPIP$SSH_SSH2.EXE: SSH Secure Shell OpenVMS
(V5.5) 3.2.0 on HP Integrity BL860c i2 (1.33GHz - VMS V8.4-2L1

[joukj]

Looks like 2 different problems to me:

  1) the key problem. Are you sure that the key on the ssh-server is not changed? If it is changed just remove the key as suggested. If it is not changed or you do not know, you may throw away the key as suggested, but that may be not realy safe. Do it only if you realy trust the ssh-server and you are realy sure you connect to the right machine and no one is relaying your IP-route to some other machine.

2) The authentication problem when connecting a ssh-server located on a OpenVMS machine. Modern linux's block some encryption methods which they do not thibnk are safe again. The ssh-server on OpenVMS is old and does not support the newer ebcryption methods. If you want to connect anyway, disable in the linux system and the ssh-server this blocking.