Recentemente, introduzimos vários novos hosts em nosso servidor. Conectividade remota estava funcionando bem, até que o sistema operacional no servidor foi reinstalado.
Após verificar os logs do servidor e do lado do cliente, descobrimos que a mensagem de erro abaixo aparece no lado do cliente, fazendo com que a conexão seja fechada pelo lado do cliente.
Error: Unexpected SSH layer 3 GLOBAL_REQUEST message received
Depois de elevar o nível de depuração no lado do servidor para DEBUG3, aqui abaixo estão os logs, parece que o servidor está enviando o pacote tipo 51 antes da desconexão. Além disso, você encontrará abaixo os logs extraídos de outro nó onde o SSH está funcionando bem.
debug3: fd 5 is not O_NONBLOCK
debug1: Forked child 2652.
debug3: send_rexec_state: entering fd = 8 config len 1085
debug3: ssh_msg_send: type 0
debug3: send_rexec_state: done
debug3: oom_adjust_restore
debug1: Set /proc/self/oom_score_adj to 0
debug1: rexec start in 5 out 5 newsock 5 pipe 7 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 10.115.33.65 port 51585 on 10.58.126.35 port 22
debug1: Client protocol version 2.0; client software version Nakina_SSH_1.0
debug1: no match: Nakina_SSH_1.0
debug1: Local version string SSH-2.0-OpenSSH_7.4
debug1: Enabling compatibility mode for protocol 2.0
debug2: fd 3 setting O_NONBLOCK
debug3: ssh_sandbox_init: preparing seccomp filter sandbox
debug2: Network child is on pid 2653
debug3: preauth child monitor started
debug1: SELinux support enabled [preauth]
debug3: ssh_selinux_change_context: setting context from 'system_u:system_r:sshd_t:s0-s0:c0.c1023' to 'system_u:system_r:sshd_net_t:s0-s0:c0.c1023' [preauth]
debug3: privsep user:group 74:74 [preauth]
debug1: permanently_set_uid: 74/74 [preauth]
debug3: ssh_sandbox_child: setting PR_SET_NO_NEW_PRIVS [preauth]
debug3: ssh_sandbox_child: attaching seccomp filter program [preauth]
debug1: list_hostkey_types: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
debug3: send packet: type 20 [preauth]
debug1: SSH2_MSG_KEXINIT sent [preauth]
debug3: receive packet: type 20 [preauth]
debug1: SSH2_MSG_KEXINIT received [preauth]
debug2: local server KEXINIT proposal [preauth]
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,diffie-hellman-group1-sha1 [preauth]
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr [preauth]
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr [preauth]
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 [preauth]
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 [preauth]
debug2: compression ctos: none,[email protected] [preauth]
debug2: compression stoc: none,[email protected] [preauth]
debug2: languages ctos: [preauth]
debug2: languages stoc: [preauth]
debug2: first_kex_follows 0 [preauth]
debug2: reserved 0 [preauth]
debug2: peer client KEXINIT proposal [preauth]
debug2: KEX algorithms: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 [preauth]
debug2: host key algorithms: ssh-rsa,ssh-dss [preauth]
debug2: ciphers ctos: aes256-cbc,aes256-ctr,aes192-cbc,aes192-ctr,aes128-cbc,aes128-ctr,3des-cbc,3des-ctr,blowfish-cbc,blowfish-ctr [preauth]
debug2: ciphers stoc: aes256-cbc,aes256-ctr,aes192-cbc,aes192-ctr,aes128-cbc,aes128-ctr,3des-cbc,3des-ctr,blowfish-cbc,blowfish-ctr [preauth]
debug2: MACs ctos: hmac-sha1,hmac-md5,hmac-sha1-96,hmac-md5-96 [preauth]
debug2: MACs stoc: hmac-sha1,hmac-md5,hmac-sha1-96,hmac-md5-96 [preauth]
debug2: compression ctos: none [preauth]
debug2: compression stoc: none [preauth]
debug2: languages ctos: [preauth]
debug2: languages stoc: [preauth]
debug2: first_kex_follows 0 [preauth]
debug2: reserved 0 [preauth]
debug1: kex: algorithm: diffie-hellman-group14-sha1 [preauth]
debug1: kex: host key algorithm: ssh-rsa [preauth]
debug1: kex: client->server cipher: aes256-ctr MAC: hmac-sha1 compression: none [preauth]
debug1: kex: server->client cipher: aes256-ctr MAC: hmac-sha1 compression: none [preauth]
debug1: kex: diffie-hellman-group14-sha1 need=32 dh_need=32 [preauth]
debug3: mm_request_send entering: type 120 [preauth]
debug3: mm_request_receive_expect entering: type 121 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 120
debug3: mm_request_send entering: type 121
debug1: kex: diffie-hellman-group14-sha1 need=32 dh_need=32 [preauth]
debug3: mm_request_send entering: type 120 [preauth]
debug3: mm_request_receive_expect entering: type 121 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 120
debug3: mm_request_send entering: type 121
debug2: bits set: 1037/2048 [preauth]
debug1: expecting SSH2_MSG_KEXDH_INIT [preauth]
debug3: receive packet: type 30 [preauth]
debug2: bits set: 1021/2048 [preauth]
debug3: mm_key_sign entering [preauth]
debug3: mm_request_send entering: type 6 [preauth]
debug3: mm_key_sign: waiting for MONITOR_ANS_SIGN [preauth]
debug3: mm_request_receive_expect entering: type 7 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 6
debug3: mm_answer_sign
debug3: mm_answer_sign: hostkey proof signature 0x55aa18906680(271)
debug3: mm_request_send entering: type 7
debug2: monitor_read: 6 used once, disabling now
debug3: send packet: type 31 [preauth]
debug3: send packet: type 21 [preauth]
debug2: set_newkeys: mode 1 [preauth]
debug1: rekey after 4294967296 blocks [preauth]
debug1: SSH2_MSG_NEWKEYS sent [preauth]
debug1: expecting SSH2_MSG_NEWKEYS [preauth]
debug3: receive packet: type 21 [preauth]
debug1: SSH2_MSG_NEWKEYS received [preauth]
debug2: set_newkeys: mode 0 [preauth]
debug1: rekey after 4294967296 blocks [preauth]
debug1: KEX done [preauth]
debug3: receive packet: type 5 [preauth]
debug3: send packet: type 6 [preauth]
debug3: receive packet: type 50 [preauth]
debug1: userauth-request for user root service ssh-connection method none [preauth]
debug1: attempt 0 failures 0 [preauth]
debug3: mm_getpwnamallow entering [preauth]
debug3: mm_request_send entering: type 8 [preauth]
debug3: mm_getpwnamallow: waiting for MONITOR_ANS_PWNAM [preauth]
debug3: mm_request_receive_expect entering: type 9 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 8
debug3: mm_answer_pwnamallow
debug2: parse_server_config: config reprocess config len 1085
debug3: mm_answer_pwnamallow: sending MONITOR_ANS_PWNAM: 1
debug3: mm_request_send entering: type 9
debug2: monitor_read: 8 used once, disabling now
debug2: input_userauth_request: setting up authctxt for root [preauth]
debug3: mm_start_pam entering [preauth]
debug3: mm_request_send entering: type 100 [preauth]
debug3: mm_inform_authserv entering [preauth]
debug3: mm_request_send entering: type 4 [preauth]
debug3: mm_inform_authrole entering [preauth]
debug3: mm_request_send entering: type 80 [preauth]
debug3: mm_auth2_read_banner entering [preauth]
debug3: mm_request_send entering: type 10 [preauth]
debug3: mm_request_receive_expect entering: type 11 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 100
debug1: PAM: initializing for "root"
debug1: PAM: setting PAM_RHOST to "10.115.33.65"
debug1: PAM: setting PAM_TTY to "ssh"
debug2: monitor_read: 100 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 4
debug3: mm_answer_authserv: service=ssh-connection, style=
debug2: monitor_read: 4 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 80
debug3: mm_answer_authrole: role=
debug2: monitor_read: 80 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 10
debug3: mm_request_send entering: type 11
debug2: monitor_read: 10 used once, disabling now
debug3: send packet: type 53 [preauth]
debug1: userauth_send_banner: sent [preauth]
debug2: input_userauth_request: try method none [preauth]
debug3: userauth_finish: failure partial=0 next methods="publickey,password" [preauth]
debug3: send packet: type 51 [preauth]
Connection closed by 10.115.33.65 port 51585 [preauth]
debug1: do_cleanup [preauth]
debug3: PAM: sshpam_thread_cleanup entering [preauth]
debug3: mm_request_send entering: type 124 [preauth]
debug3: mm_request_send entering: type 122 [preauth]
debug3: mm_request_receive_expect entering: type 123 [preauth]
debug3: mm_request_receive entering [preauth]
debug3: mm_request_receive entering
debug3: monitor_read: checking request 124
debug3: mm_request_receive entering
debug3: monitor_read: checking request 122
debug3: mm_request_send entering: type 123
debug1: monitor_read_log: child log fd closed
debug3: mm_request_receive entering
debug1: do_cleanup
debug1: PAM: cleanup
debug3: PAM: sshpam_thread_cleanup entering
debug1: Killing privsep child 2653
Aqui estão os registros para o nó de trabalho
debug1: Forked child 30048.
Set /proc/self/oom_score_adj to 0
debug1: rexec start in 5 out 5 newsock 5 pipe 7 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 10.115.33.64 port 53628 on 10.58.105.46 port 22
debug1: Client protocol version 2.0; client software version Nakina_SSH_1.0
debug1: no match: Nakina_SSH_1.0
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1
debug1: SELinux support enabled [preauth]
debug1: permanently_set_uid: 74/74 [preauth]
debug1: list_hostkey_types: ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
debug1: SSH2_MSG_KEXINIT sent [preauth]
debug1: SSH2_MSG_KEXINIT received [preauth]
debug1: kex: client->server aes256-cbc hmac-sha1 none [preauth]
debug1: kex: server->client aes256-cbc hmac-sha1 none [preauth]
debug1: kex: diffie-hellman-group14-sha1 need=32 dh_need=32 [preauth]
debug1: kex: diffie-hellman-group14-sha1 need=32 dh_need=32 [preauth]
debug1: expecting SSH2_MSG_KEXDH_INIT [preauth]
debug1: SSH2_MSG_NEWKEYS sent [preauth]
debug1: expecting SSH2_MSG_NEWKEYS [preauth]
debug1: SSH2_MSG_NEWKEYS received [preauth]
debug1: KEX done [preauth]
debug1: userauth-request for user root service ssh-connection method none [preauth]
debug1: attempt 0 failures 0 [preauth]
debug1: PAM: initializing for "root"
debug1: PAM: setting PAM_RHOST to "10.115.33.64"
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth_send_banner: sent [preauth]
debug1: userauth-request for user root service ssh-connection method password [preauth]
debug1: attempt 1 failures 0 [preauth]
debug1: PAM: password authentication accepted for root
debug1: do_pam_account: called
Accepted password for root from 10.115.33.64 port 53628 ssh2
debug1: monitor_child_preauth: root has been authenticated by privileged process
debug1: monitor_read_log: child log fd closed
debug1: SELinux support enabled
debug1: PAM: establishing credentials
pam_unix(sshd:session): session opened for user root by (uid=0)
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 131072 max 32768
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: session 0
debug1: session_open: channel 0
debug1: session_open: session 0: link with channel 0
debug1: server_input_channel_open: confirm session
debug1: server_input_channel_req: channel 0 request pty-req reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req pty-req
debug1: Allocating pty.
debug1: session_pty_req: session 0 alloc /dev/pts/4
debug1: SELinux support enabled
debug1: server_input_channel_req: channel 0 request shell reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req shell
Starting session: shell on pts/4 for root from 10.115.33.64 port 53628
debug1: Setting controlling tty using TIOCSCTTY.
debug1: PAM: reinitializing credentials
debug1: permanently_set_uid: 0/0
Tags ssh openssh linux connectivity