ssh-keygen
ssh-copy-id -i id_rsa.pub user@server
ssh user@server
$ ssh -v user@server
OpenSSH_7.7p1, LibreSSL 2.7.3
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug1: /etc/ssh/ssh_config line 52: Applying options for *
debug1: Connecting to user@server port 22.
debug1: Connection established.
debug1: identity file /Users/kirill/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ed25519-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_xmss type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.7
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4
debug1: match: OpenSSH_7.6p1 Ubuntu-4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to (del):22 as '(del)'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
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 SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: (del)
debug1: Host '(del)' is known and matches the ED25519 host key.
debug1: Found key in /Users/kirill/.ssh/known_hosts:4
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:(del) /Users/kirill/.ssh/id_rsa
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /Users/kirill/.ssh/id_dsa
debug1: Trying private key: /Users/kirill/.ssh/id_ecdsa
debug1: Trying private key: /Users/kirill/.ssh/id_ed25519
debug1: Trying private key: /Users/kirill/.ssh/id_xmss
debug1: Next authentication method: password
user@server's password:
$ ssh -v user@server
OpenSSH_7.7p1, LibreSSL 2.7.3
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug1: /etc/ssh/ssh_config line 52: Applying options for *
debug1: Connecting to user@server port 22.
debug1: Connection established.
debug1: identity file /Users/kirill/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_ed25519-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_xmss type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/kirill/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.7
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4
debug1: match: OpenSSH_7.6p1 Ubuntu-4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to (del):22 as '(del)'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
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 SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: (del)
debug1: Host '(del)' is known and matches the ED25519 host key.
debug1: Found key in /Users/kirill/.ssh/known_hosts:4
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:(del) /Users/kirill/.ssh/id_rsa
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /Users/kirill/.ssh/id_dsa
debug1: Trying private key: /Users/kirill/.ssh/id_ecdsa
debug1: Trying private key: /Users/kirill/.ssh/id_ed25519
debug1: Trying private key: /Users/kirill/.ssh/id_xmss
debug1: Next authentication method: password
user@server's password:
authorized_keys
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile %h/.ssh/authorized_keys
~/.ssh/config
Host someip
HostName someip
Port 22
User someuser
IdentityFile ~/.ssh/someprivatekey