Linux命令（5）ssh

Posted on In Word count in article: 2.2k Reading time ≈ 8 mins.

配置公钥

使用的系统是Centos7.9，并且已经提前生成好了ssh密钥。

首先进入自己的home目录创建.ssh文件夹。

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$ cd
$ mkdir .ssh

在.ssh文件夹内创建授权文件。

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$ cd ~/.ssh
$ touch authorized_keys

然后把已经生成的id_rsa.pub内容复制进去。

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$ cat authorized_keys
ssh-rsa ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDhJQ/8nTVaTKSkuFI598trm2bJ0/5ACD6eNiGNhG2Fzv2t+ZE5VAMU1Eo68YAe00LMPhuEFC60+uSUDj0AzKp4SCW6HfDoiiTJVei+uAS8xEi//LUu8i0amaiSVNSRi4NrmWUVv8cUhVsbz9S0xLLhOBqWLlClxZJNAT2p1FG7jnq1tugiCJXJ/OC31zpfwdwRJr/RmY+gldj0baobFHvuAY+pLqIeviQtytybXVNp62xMpXJ3ntmz5/KkSCwrLNWevqHgsX6brlG9Oh8grDxczz1Dn6ccVADg9yWUaRJg3uNtLingIOZd+j+FotxJ1tsKmQr8BJacYg6+1N50SQp5 sunsh@hostname

重新登录，发现还是需要输入密码。

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$ ssh shuyi@192.168.0.112
shuyi@192.168.0.112's password:

此时还不够，直接通过ssh登录还是输入密码，因为.ssh权限设置过于开放，需要收紧一些。

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$ sudo chmod 700 ~/.ssh
$ sudo chmod 600 ~/.ssh/authorized_keys

再次登录就能直接进来了。

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[long@localhost ~]$ ssh shuyi@192.168.0.112
Last login: Mon Jul 10 21:48:42 2023 from 192.168.0.114
[shuyi@bogon ~]$

连接debug

ssh连接有时候可能会出现问题无法连接上，可以使用-v参数查看debug日志。

这个选项通常可以用来排查连接、认证和配置问题，多个-v选项可以增加信息，最多三个。

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$ ssh -vvv shuyi@192.168.0.112
OpenSSH_8.2p1 Ubuntu-4, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/long/.ssh/config
debug1: /home/long/.ssh/config line 1: Applying options for *
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 192.168.0.112 is address
debug1: auto-mux: Trying existing master
debug1: Control socket "/home/long/.ssh/master-shuyi@192.168.0.112:22" does not exist
debug2: ssh_connect_direct
debug1: Connecting to 192.168.0.112 [192.168.0.112] port 22.
debug1: Connection established.
debug1: identity file /home/long/.ssh/id_rsa type 0
debug1: identity file /home/long/.ssh/id_rsa-cert type -1
debug1: identity file /home/long/.ssh/id_dsa type -1
debug1: identity file /home/long/.ssh/id_dsa-cert type -1
debug1: identity file /home/long/.ssh/id_ecdsa type -1
debug1: identity file /home/long/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/long/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/long/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/long/.ssh/id_ed25519 type -1
debug1: identity file /home/long/.ssh/id_ed25519-cert type -1
debug1: identity file /home/long/.ssh/id_ed25519_sk type -1
debug1: identity file /home/long/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/long/.ssh/id_xmss type -1
debug1: identity file /home/long/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.0.112:22 as 'shuyi'
debug3: hostkeys_foreach: reading file "/home/long/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/long/.ssh/known_hosts:14
debug3: load_hostkeys: loaded 1 keys from 192.168.0.112
debug3: order_hostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,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,curve25519-sha256@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@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,ssh-ed25519,sk-ssh-ed25519@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@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@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-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@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@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com 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 SHA256:2VTV10Q0Df1cSA99eyfGhFfPxhlSsxYLtdJ75oKWFTU
debug3: hostkeys_foreach: reading file "/home/long/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/long/.ssh/known_hosts:14
debug3: load_hostkeys: loaded 1 keys from 192.168.0.112
debug1: Host '192.168.0.112' is known and matches the ECDSA host key.
debug1: Found key in /home/long/.ssh/known_hosts:14
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out 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 in after 134217728 blocks
debug1: Will attempt key: /home/long/.ssh/id_rsa RSA SHA256:Y9K5bCXNtPZ816HGgqjKnVaxMNkEP+e1HazGZIil7wk
debug1: Will attempt key: /home/long/.ssh/id_dsa
debug1: Will attempt key: /home/long/.ssh/id_ecdsa
debug1: Will attempt key: /home/long/.ssh/id_ecdsa_sk
debug1: Will attempt key: /home/long/.ssh/id_ed25519
debug1: Will attempt key: /home/long/.ssh/id_ed25519_sk
debug1: Will attempt key: /home/long/.ssh/id_xmss
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
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,gssapi-keyex,gssapi-with-mic,password
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_1000)


debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_1000)


debug2: we did not send a packet, disable method
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/long/.ssh/id_rsa RSA SHA256:Y9K5bCXNtPZ816HGgqjKnVaxMNkEP+e1HazGZIil7wk
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: /home/long/.ssh/id_rsa RSA SHA256:Y9K5bCXNtPZ816HGgqjKnVaxMNkEP+e1HazGZIil7wk
debug3: sign_and_send_pubkey: RSA SHA256:Y9K5bCXNtPZ816HGgqjKnVaxMNkEP+e1HazGZIil7wk
debug3: sign_and_send_pubkey: signing using rsa-sha2-512 SHA256:Y9K5bCXNtPZ816HGgqjKnVaxMNkEP+e1HazGZIil7wk
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to 192.168.0.112 ([192.168.0.112]:22).
debug1: setting up multiplex master socket
debug3: muxserver_listen: temporary control path /home/long/.ssh/master-shuyi@192.168.0.112:22.ZSkIir8Jj5y0HNw0
debug2: fd 4 setting O_NONBLOCK
debug3: fd 4 is O_NONBLOCK
debug3: fd 4 is O_NONBLOCK
debug1: channel 0: new [/home/long/.ssh/master-shuyi@192.168.0.112:22]
debug3: muxserver_listen: mux listener channel 0 fd 4
debug1: channel 1: new [client-session]
debug3: ssh_session2_open: channel_new: 1
debug2: channel 1: send open
debug3: send packet: type 90
debug1: Entering interactive session.
debug1: pledge: id
debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 1: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 1
debug2: channel 1: request pty-req confirm 1
debug3: send packet: type 98
debug1: Sending environment.
debug3: Ignored env SHELL
debug3: Ignored env WSL_DISTRO_NAME
debug3: Ignored env NAME
debug3: Ignored env PWD
debug3: Ignored env LOGNAME
debug3: Ignored env MOTD_SHOWN
debug3: Ignored env HOME
debug1: Sending env LANG = C.UTF-8
debug2: channel 1: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env LS_COLORS
debug3: Ignored env LESSCLOSE
debug3: Ignored env TERM
debug3: Ignored env LESSOPEN
debug3: Ignored env USER
debug3: Ignored env SHLVL
debug3: Ignored env PS1
debug3: Ignored env WSLENV
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env PATH
debug3: Ignored env HOSTTYPE
debug3: Ignored env _
debug2: channel 1: request shell confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 1: callback done
debug2: channel 1: open confirm rwindow 0 rmax 32768
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 1
debug2: PTY allocation request accepted on channel 1
debug2: channel 1: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 1
debug2: shell request accepted on channel 1
Last login: Mon Jul 10 21:57:08 2023 from 192.168.0.114
[shuyi@bogon ~]$

如果是由一个-v选项，就只能打印debug1的日志。

同时退出的时候也会打印出日志来。

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$ exitdebug3: receive packet: type 98
debug1: client_input_channel_req: channel 1 rtype exit-status reply 0
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 1 rtype eow@openssh.com reply 0
debug2: channel 1: rcvd eow
debug2: channel 1: chan_shutdown_read (i0 o0 sock -1 wfd 5 efd 7 [write])
debug2: channel 1: input open -> closed

logout
debug3: receive packet: type 96
debug2: channel 1: rcvd eof
debug2: channel 1: output open -> drain
debug2: channel 1: obuf empty
debug2: channel 1: chan_shutdown_write (i3 o1 sock -1 wfd 6 efd 7 [write])
debug2: channel 1: output drain -> closed
debug3: receive packet: type 97
debug2: channel 1: rcvd close
debug3: channel 1: will not send data after close
debug2: channel 1: almost dead
debug2: channel 1: gc: notify user
debug2: channel 1: gc: user detached
debug2: channel 1: send close
debug3: send packet: type 97
debug2: channel 1: is dead
debug2: channel 1: garbage collecting
debug1: channel 1: free: client-session, nchannels 2
debug3: channel 1: status: The following connections are open:
  #1 client-session (t4 r0 i3/0 o3/0 e[write]/0 fd -1/-1/7 sock -1 cc -1)

debug3: send packet: type 1
debug1: channel 0: free: /home/long/.ssh/master-shuyi@192.168.0.112:22, nchannels 1
debug3: channel 0: status: The following connections are open:

debug3: fd 1 is not O_NONBLOCK
Connection to 192.168.0.112 closed.
Transferred: sent 3332, received 3228 bytes, in 4.0 seconds
Bytes per second: sent 826.8, received 801.0
debug1: Exit status 0