Cannot root login via SSH to Centos 7 on Digitalocean anymore

August 21, 2019 273 views
Development CentOS
hellodigitalworld
By:
hellodigitalworld

Hi I had set up SSH login to my Centos droplet and disabled login via a password. It has been working fine for a year. I haven’t ssh'ed into the droplet for a few months and now when I try to I get an error - “Permission Denied”. The machine I connect from hasn’t changed. The keys from the Windows 10 machine I connect from were previously installed on the droplet and worked fine for a year.
I guess I’m locked out of the droplet now. But my main question is: why did this happen and how do I make sure it does not happen in the future?

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2 Answers
bobbyiliev MOD August 22, 2019

Hello,

Here’s a step by step guide on how to get access back to your droplet:

https://www.digitalocean.com/docs/droplets/resources/lost-ssh-key/

Regarding, preventing this from happening. Can you share some more information here regarding the following:

  • What software are you using to connect?

  • What is the full error that you are getting?

Usually if get Permission denied (publickey), this could be due to one of the following:

  • You don’t have the matching key on your local machine
  • If you are using Putty, then maybe the location of your Public key changed and it is no longer loaded by Putty

Hope that this helps!
Regards,
Bobby

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hellodigitalworld August 23, 2019

Thank you for your response. I’m using Windows 10 ubuntu bash.
I still cannot gain access to the droplet.
I have also verified that public key in /home/alex/.ssh/id_rsa.pub is registered on digitialocean SSH Keys. Again, it was working a few months ago and I haven’t made any changes.

Here is what I get when trying to ssh

OpenSSH7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g 1 Mar 2016
debug1: Reading configuration data /etc/ssh/sshconfig
debug1: /etc/ssh/sshconfig line 19: Applying options for *
debug1: Connecting to 204.48.25.76 [204.48.25.76] port 22.
debug1: Connection established.
debug1: identity file /home/alex/.ssh/idrsa type 1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/idrsa-cert type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/iddsa type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/iddsa-cert type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/idecdsa type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/idecdsa-cert type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/ided25519 type -1
debug1: keyloadpublic: No such file or directory
debug1: identity file /home/alex/.ssh/ided25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH7.2p2 Ubuntu-4ubuntu2.2
debug1: Remote protocol version 2.0, remote software version OpenSSH7.4
debug1: match: OpenSSH7.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to 204.48.25.76:22 as ‘root’
debug1: SSH2MSGKEXINIT sent
debug1: SSH2MSGKEXINIT received
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2MSGKEXECDHREPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:SR/xqDyLwnjPxx3/zW2PZ6dgjLP+Jqcou/kcHRCn66o
debug1: Host '204.48.25.76’ is known and matches the ECDSA host key.
debug1: Found key in /home/alex/.ssh/knownhosts:6
debug1: rekey after 134217728 blocks
debug1: SSH2MSGNEWKEYS sent
debug1: expecting SSH2MSGNEWKEYS
debug1: rekey after 134217728 blocks
debug1: SSH2MSGNEWKEYS received
debug1: SSH2MSGEXTINFO received
debug1: kexinputextinfo: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2MSGSERVICEACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Unspecified GSS failure. Minor code may provide more information

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available
debug2: we did not send a packet, disable method
debug3: authmethodlookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethodisenabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/alex/.ssh/idrsa
debug3: sendpubkeytest
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug2: inputuserauthpkok: fp SHA256:KJrwF9jZnErKFdVEq4OUbaaZqNUTgzwhC+wZow3Mx7U
debug3: signandsendpubkey: RSA SHA256:KJrwF9jZnErKFdVEq4OUbaaZqNUTgzwhC+wZow3Mx7U
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Trying private key: /home/alex/.ssh/iddsa
debug3: no such identity: /home/alex/.ssh/iddsa: No such file or directory
debug1: Trying private key: /home/alex/.ssh/idecdsa
debug3: no such identity: /home/alex/.ssh/idecdsa: No such file or directory
debug1: Trying private key: /home/alex/.ssh/ided25519
debug3: no such identity: /home/alex/.ssh/ided25519: No such file or directory
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

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