当我将我的公钥复制到服务器时，ssh-copy-id服务器会主动拒绝我的连接，并出现简单的类型 51 故障。
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n 7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "srv2.euroexpress.ba" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to srv2.euroexpress.ba [217.24.137.67] port 22.
debug1: Connection established.
debug1: identity file /home/ognjen/.ssh/id_rsa.pub type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/ognjen/.ssh/id_rsa.pub-cert type -1
debug1: identity file /home/ognjen/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/ognjen/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to srv2.euroexpress.ba:22 as 'ubuntu'
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:21
debug3: load_hostkeys: loaded 1 keys from srv2.euroexpress.ba
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],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,[email protected],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,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
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: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:Tm8InBcntxskXCE3QLLydzbXDHptDFANbmxx1oeav4U
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:21
debug3: load_hostkeys: loaded 1 keys from srv2.euroexpress.ba
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:18
debug3: load_hostkeys: loaded 1 keys from 217.24.137.67
debug1: Host 'srv2.euroexpress.ba' is known and matches the ECDSA host key.
debug1: Found key in /home/ognjen/.ssh/known_hosts:21
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /home/ognjen/.ssh/id_rsa.pub (0x55b8f444abf0), explicit, agent
debug2: key: /home/ognjen/.ssh/id_rsa (0x55b8f44577c0)
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: password
debug3: start over, passed a different list password
debug3: preferred publickey
debug1: No more authentication methods to try.
[email protected]: Permission denied (password).
一个简单的解决方法是以 root 身份在不同的端口上手动启动守护进程：
# /usr/sbin/sshd -D -d -e -p 80 -f /etc/ssh/sshd_config
然后，在不同的端口上使用相同的命令、配置、客户端和守护程序二进制文件，一切正常：
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n 7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "srv2.euroexpress.ba" port 80
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to srv2.euroexpress.ba [217.24.137.67] port 80.
debug1: Connection established.
debug1: identity file /home/ognjen/.ssh/id_rsa.pub type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/ognjen/.ssh/id_rsa.pub-cert type -1
debug1: identity file /home/ognjen/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/ognjen/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to srv2.euroexpress.ba:80 as 'ubuntu'
debug3: put_host_port: [srv2.euroexpress.ba]:80
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:22
debug3: load_hostkeys: loaded 1 keys from [srv2.euroexpress.ba]:80
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],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,[email protected],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,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
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: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:5EaeFSj8YH5+W+RPW5mQc7hwtD3A5Gq0QeFyPYTt+eE
debug3: put_host_port: [217.24.137.67]:80
debug3: put_host_port: [srv2.euroexpress.ba]:80
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:22
debug3: load_hostkeys: loaded 1 keys from [srv2.euroexpress.ba]:80
debug3: hostkeys_foreach: reading file "/home/ognjen/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/ognjen/.ssh/known_hosts:23
debug3: load_hostkeys: loaded 1 keys from [217.24.137.67]:80
debug1: Host '[srv2.euroexpress.ba]:80' is known and matches the ECDSA host key.
debug1: Found key in /home/ognjen/.ssh/known_hosts:22
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /home/ognjen/.ssh/id_rsa.pub (0x555da0469bf0), explicit, agent
debug2: key: /home/ognjen/.ssh/id_rsa (0x555da04767c0)
debug3: send packet: type 5
debug3: receive packet: type 7
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>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey
debug3: authmethod_lookup publickey
debug3: remaining preferred:
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:HX7ZtVhHTzHP8djnbaGRBrTYdNmu92E5PsNRERe7bc8 /home/ognjen/.ssh/id_rsa.pub
debug3: send_pubkey_test
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: input_userauth_pk_ok: fp SHA256:HX7ZtVhHTzHP8djnbaGRBrTYdNmu92E5PsNRERe7bc8
debug3: sign_and_send_pubkey: RSA SHA256:HX7ZtVhHTzHP8djnbaGRBrTYdNmu92E5PsNRERe7bc8
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to srv2.euroexpress.ba ([217.24.137.67]:80).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting [email protected]
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug3: send packet: type 98
debug1: Sending environment.
debug3: Ignored env LS_COLORS
debug1: Sending env LC_MEASUREMENT = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env LESSCLOSE
debug1: Sending env LC_PAPER = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug1: Sending env LC_MONETARY = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env GDM_LANG
debug3: Ignored env DISPLAY
debug3: Ignored env COMPIZ_CONFIG_PROFILE
debug3: Ignored env GTK_OVERLAY_SCROLLING
debug3: Ignored env COLORTERM
debug3: Ignored env XDG_VTNR
debug3: Ignored env SSH_AUTH_SOCK
debug3: Ignored env MANDATORY_PATH
debug1: Sending env LC_NAME = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env XDG_SESSION_ID
debug3: Ignored env XDG_GREETER_DATA_DIR
debug3: Ignored env USER
debug3: Ignored env DESKTOP_SESSION
debug3: Ignored env DEFAULTS_PATH
debug3: Ignored env QT_QPA_PLATFORMTHEME
debug3: Ignored env PWD
debug3: Ignored env HOME
debug3: Ignored env SSH_AGENT_PID
debug3: Ignored env QT_ACCESSIBILITY
debug3: Ignored env XDG_SESSION_TYPE
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env MATE_DESKTOP_SESSION_ID
debug3: Ignored env XDG_SESSION_DESKTOP
debug3: Ignored env QT_SCALE_FACTOR
debug1: Sending env LC_ADDRESS = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug1: Sending env LC_NUMERIC = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env GTK_MODULES
debug3: Ignored env UBUNTU_MENUPROXY
debug3: Ignored env SHELL
debug3: Ignored env VTE_VERSION
debug3: Ignored env TERM
debug3: Ignored env XDG_SEAT_PATH
debug3: Ignored env XDG_CURRENT_DESKTOP
debug3: Ignored env GPG_AGENT_INFO
debug3: Ignored env XDG_SEAT
debug3: Ignored env SHLVL
debug3: Ignored env LANGUAGE
debug3: Ignored env WINDOWID
debug1: Sending env LC_TELEPHONE = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env GDMSESSION
debug3: Ignored env LOGNAME
debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
debug3: Ignored env XDG_RUNTIME_DIR
debug3: Ignored env XAUTHORITY
debug3: Ignored env XDG_SESSION_PATH
debug3: Ignored env QT_AUTO_SCREEN_SCALE_FACTOR
debug3: Ignored env XDG_CONFIG_DIRS
debug3: Ignored env PATH
debug1: Sending env LC_IDENTIFICATION = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env SESSION_MANAGER
debug3: Ignored env LESSOPEN
debug1: Sending env LC_TIME = bs_BA.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env _
debug3: Ignored env OLDPWD
debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Welcome to Ubuntu 18.04.2 LTS (GNU/Linux 4.15.0-55-generic x86_64)
这发生在我们堆栈中的两台不同的机器上，均为非本地机器。
答案1
我会检查服务器日志sshd是否可以读取授权密钥文件。
此后，我会检查输出systemctl cat sshd并寻找任何特殊的东西。
此外，检查sshd运行受限应用装甲（ps auxZ）。如果是，请检查审计对于DENIED线条。