SSH key question

Thu Dec 10 19:55:00 UTC 2020

On Thu, Dec 10, 2020 at 10:39 AM Sarunas Burdulis
<sarunas at math.dartmouth.edu> wrote:
>
:
>
> I don't know what the problem may be, but increased verbosity of SSH
> connenction may shed some light.
>
> ssh -vv ...
>
Here's what I see (from laptop marHP8740 to desktop marbase):

11:50 [admar at marHP8740w:~] $ ssh -vv $BASE
OpenSSH_8.2p1 Ubuntu-4ubuntu0.1, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include
/etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 192.168.1.131 is address
debug2: ssh_connect_direct
debug1: Connecting to 192.168.1.131 [192.168.1.131] port 22.
debug1: Connection established.
debug1: identity file /home/admar/.ssh/id_rsa type 0
debug1: identity file /home/admar/.ssh/id_rsa-cert type -1
debug1: identity file /home/admar/.ssh/id_dsa type -1
debug1: identity file /home/admar/.ssh/id_dsa-cert type -1
debug1: identity file /home/admar/.ssh/id_ecdsa type -1
debug1: identity file /home/admar/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/admar/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/admar/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/admar/.ssh/id_ed25519 type -1
debug1: identity file /home/admar/.ssh/id_ed25519-cert type -1
debug1: identity file /home/admar/.ssh/id_ed25519_sk type -1
debug1: identity file /home/admar/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/admar/.ssh/id_xmss type -1
debug1: identity file /home/admar/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
debug1: Remote protocol version 2.0, remote software version
OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
debug1: match: OpenSSH_8.2p1 Ubuntu-4ubuntu0.1 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.1.131:22 as 'admar'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms:
curve25519-sha256,curve25519-sha256 at libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c
debug2: host key algorithms:
ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256-cert-v01 at openssh.com,ssh-ed25519-cert-v01 at openssh.com,sk-ssh-ed25519-cert-v01 at openssh.com,rsa-sha2-512-cert-v01 at openssh.com,rsa-sha2-256-cert-v01 at openssh.com,ssh-rsa-cert-v01 at openssh.com,sk-ecdsa-sha2-nistp256 at openssh.com,ssh-ed25519,sk-ssh-ed25519 at openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos:
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com
debug2: ciphers stoc:
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com
debug2: MACs ctos:
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc:
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com,zlib
debug2: compression stoc: none,zlib at openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms:
curve25519-sha256,curve25519-sha256 at libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256
debug2: host key algorithms:
rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos:
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com
debug2: ciphers stoc:
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com
debug2: MACs ctos:
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc:
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com
debug2: compression stoc: none,zlib at openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256
SHA256:liK5yK4l533NSr9JYUrxyXMi69UIWAhZ7vz9LRC7Mhs
debug1: Host '192.168.1.131' is known and matches the ECDSA host key.
debug1: Found key in /home/admar/.ssh/known_hosts:1
debug2: set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/admar/.ssh/id_rsa RSA
SHA256:6ipcSUwJHMccKD1XhUx8I1TSVgLbpyBc2INdxzYzJy0
debug1: Will attempt key: /home/admar/.ssh/id_dsa
debug1: Will attempt key: /home/admar/.ssh/id_ecdsa
debug1: Will attempt key: /home/admar/.ssh/id_ecdsa_sk
debug1: Will attempt key: /home/admar/.ssh/id_ed25519
debug1: Will attempt key: /home/admar/.ssh/id_ed25519_sk
debug1: Will attempt key: /home/admar/.ssh/id_xmss
debug2: pubkey_prepare: done
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info:
server-sig-algs=<ssh-ed25519,sk-ssh-ed25519 at openssh.com,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256 at openssh.com>
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: /home/admar/.ssh/id_rsa RSA
SHA256:6ipcSUwJHMccKD1XhUx8I1TSVgLbpyBc2INdxzYzJy0
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/admar/.ssh/id_dsa
debug1: Trying private key: /home/admar/.ssh/id_ecdsa
debug1: Trying private key: /home/admar/.ssh/id_ecdsa_sk
debug1: Trying private key: /home/admar/.ssh/id_ed25519
debug1: Trying private key: /home/admar/.ssh/id_ed25519_sk
debug1: Trying private key: /home/admar/.ssh/id_xmss
debug2: we did not send a packet, disable method
debug1: Next authentication method: password
admar at 192.168.1.131's password:

I'm not 100% sure of what each step of that means, but the bottom line
is pretty clear - the authentication failed and it wants a password.

Hope that makes sense to someone.

Thanks.

Mark