Conexão SSH perdida após intervalo de tempo aleatório, ambos os lados afirmam que o outro fechou a conexão

Conexão SSH perdida após intervalo de tempo aleatório, ambos os lados afirmam que o outro fechou a conexão

Estou me conectando a uma máquina virtual Solaris do sistema host do Windows executando a caixa virtual. Isso funciona por um tempo, mas depois de algum tempo a conexão desaparece.

O estranho é que o sshd afirma que a conexão foi redefinida pelo peer, enquanto a sessão ssh diz que a conexão foi fechada pelo host remoto.

Consegui iniciar o sshd manualmente ( /usr/lib/ssh/sshd -d), para obter a saída de depuração mostrada abaixo, mas não sei como proceder.

Coisas tentadas até agora:

  • Verifique /var/log/authlog: está vazio
  • Verifique se os pacotes estão atualizados (pkgchk -n SUNWsshcu, pkgchk -n SUNWsshdr, pkgchk -n SUNWsshdu, pkgchk -n SUNWsshhr, pkgchk -n SUNWsshr, pkgchk -n SUNWsshu): todos atualizados
  • Permitir login com senha em /etc/ssh/ssh_configPasswordAuthentication sim e usar isso: sem alteração

Pergunta: Estou travado, como posso continuar trabalhando no problema?


Mais Informações:

Iniciando o daemon ssh:

bash-3.2# /usr/lib/ssh/sshd -d
debug1: sshd version Sun_SSH_1.1.5
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug1: read PEM private key done: type DSA
debug1: private host key: #1 type 2 DSA
debug1: Bind to port 22 on ::.
Server listening on :: port 22.

Conectando remotamente:

debug1: Server will not fork when running in debugging mode.
Connection from 10.0.2.2 port 26688
debug1: Client protocol version 2.0; client software version OpenSSH_6.2
debug1: match: OpenSSH_6.2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-Sun_SSH_1.1.5
monitor debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: use_engine is 'yes'
monitor debug1: reading the context from the child
debug1: pkcs11 engine initialized, now setting it as default for RSA, DSA, and symmetric ciphers
debug1: pkcs11 engine initialization complete
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: client->server aes128-ctr hmac-md5 zlib
debug1: kex: server->client aes128-ctr hmac-md5 zlib
debug1: Peer sent proposed langtags, ctos:
debug1: Peer sent proposed langtags, stoc:
debug1: We proposed langtags, ctos: i-default
debug1: We proposed langtags, stoc: i-default
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: dh_gen_key: priv key bits set: 134/256
debug1: bits set: 526/1024
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug1: bits set: 497/1024
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: newkeys: mode 1
debug1: set_newkeys: setting new keys for 'out' mode
debug1: Enabling compression at level 6.
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: set_newkeys: setting new keys for 'in' mode
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user beginner service ssh-connection method none
debug1: attempt 0 initial attempt 0 failures 0 initial failures 0
Failed none for beginn from 10.0.2.2 port 26688 ssh2
debug1: userauth-request for user beginner service ssh-connection method passworddebug1: attempt 1 initial attempt 0 failures 1 initial failures 0
Accepted password for beginner from 10.0.2.2 port 26688 ssh2
debug1: permanently_set_uid: 54324/1
debug1: sending auth context to the monitor
debug1: will send 41 bytes of auth context to the monitor
monitor debug1: finished reading the context
monitor debug1: use_engine is 'yes'
monitor debug1: pkcs11 engine initialized, now setting it as default for RSA, DSA, and symmetric ciphers
monitor debug1: pkcs11 engine initialization complete
monitor debug1: Entering monitor loop.
monitor debug1: fd 9 setting O_NONBLOCK
monitor debug1: fd 10 setting O_NONBLOCK
debug1: Entering interactive session for SSH2.
debug1: fd 9 setting O_NONBLOCK
debug1: fd 10 setting O_NONBLOCK
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 1048576 max 16384
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: init
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 x11-req reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req x11-req
debug1: bind port 6010: Address already in use; skipping this port
debug1: bind port 6011: Address already in use; skipping this port
debug1: bind port 6012: Address already in use; skipping this port
debug1: bind port 6013: Address already in use; skipping this port
debug1: fd 11 setting O_NONBLOCK
debug1: channel 1: new [X11 inet listener]
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/8
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
debug1: Setting controlling tty using TIOCSCTTY.
debug1: fd 4 setting TCP_NODELAY
debug1: SSH receive window size: 198560 B
debug1: fd 13 setting O_NONBLOCK

Iniciando o emacs e trabalhando por algum tempo:

debug1: server_input_global_request: rtype [email protected] want_reply 1
debug1: server_input_global_request: rtype [email protected] want_reply 1
debug1: X11 connection requested.
debug1: fd 16 setting TCP_NODELAY
debug1: channel 2: new [X11 connection from 127.0.0.1 port 33079]
debug1: channel 2: open confirm rwindow 2097152 rmax 16384
debug1: channel 2: read<=0 rfd 16 len 0
debug1: channel 2: read failed
debug1: channel 2: close_read
debug1: channel 2: input open -> drain
debug1: channel 2: ibuf empty
debug1: channel 2: send eof
debug1: channel 2: input drain -> closed
debug1: channel 2: rcvd eof
debug1: channel 2: output open -> drain
debug1: channel 2: obuf empty
debug1: channel 2: close_write
debug1: channel 2: output drain -> closed
debug1: channel 2: rcvd close
debug1: channel 2: send close
debug1: channel 2: is dead
debug1: channel 2: garbage collecting
debug1: channel_free: channel 2: X11 connection from 127.0.0.1 port 33079, nchan nels 3
debug1: X11 connection requested.
debug1: fd 16 setting TCP_NODELAY
debug1: channel 2: new [X11 connection from 127.0.0.1 port 33080]
debug1: channel 2: open confirm rwindow 2097152 rmax 16384
debug1: channel 2: read<=0 rfd 16 len 0
debug1: channel 2: read failed
debug1: channel 2: close_read
debug1: channel 2: input open -> drain
debug1: channel 2: ibuf empty
debug1: channel 2: send eof
debug1: channel 2: input drain -> closed
debug1: X11 connection requested.
debug1: fd 17 setting TCP_NODELAY
debug1: channel 3: new [X11 connection from 127.0.0.1 port 33081]
debug1: channel 2: rcvd eof
debug1: channel 2: output open -> drain
debug1: channel 2: obuf empty
debug1: channel 2: close_write
debug1: channel 2: output drain -> closed
debug1: channel 2: rcvd close
debug1: channel 2: send close
debug1: channel 2: is dead
debug1: channel 2: garbage collecting
debug1: channel_free: channel 2: X11 connection from 127.0.0.1 port 33080, nchan nels 4
debug1: channel 3: open confirm rwindow 2097152 rmax 16384
debug1: channel 3: read<=0 rfd 17 len 0
debug1: channel 3: read failed
debug1: channel 3: close_read
debug1: channel 3: input open -> drain
debug1: channel 3: ibuf empty
debug1: channel 3: send eof
debug1: channel 3: input drain -> closed
debug1: channel 3: rcvd eof
debug1: channel 3: output open -> drain
debug1: channel 3: obuf empty
debug1: channel 3: close_write
debug1: channel 3: output drain -> closed
debug1: channel 3: send close
debug1: channel 3: rcvd close
debug1: channel 3: is dead
debug1: channel 3: garbage collecting
debug1: channel_free: channel 3: X11 connection from 127.0.0.1 port 33081, nchan nels 3
debug1: X11 connection requested.
debug1: fd 16 setting TCP_NODELAY
debug1: channel 2: new [X11 connection from 127.0.0.1 port 33084]
debug1: channel 2: open confirm rwindow 2097152 rmax 16384
debug1: X11 connection requested.
debug1: fd 17 setting TCP_NODELAY
debug1: channel 3: new [X11 connection from 127.0.0.1 port 33085]
debug1: channel 2: read<=0 rfd 16 len 0
debug1: channel 2: read failed
debug1: channel 2: close_read
debug1: channel 2: input open -> drain
debug1: channel 2: ibuf empty
debug1: channel 2: send eof
debug1: channel 2: input drain -> closed
debug1: channel 3: open confirm rwindow 2097152 rmax 16384
debug1: channel 2: rcvd eof
debug1: channel 2: output open -> drain
debug1: channel 2: obuf empty
debug1: channel 2: close_write
debug1: channel 2: output drain -> closed
debug1: channel 2: rcvd close
debug1: channel 2: send close
debug1: channel 2: is dead
debug1: channel 2: garbage collecting
debug1: channel_free: channel 2: X11 connection from 127.0.0.1 port 33084, nchan nels 4
debug1: X11 connection requested.
debug1: fd 16 setting TCP_NODELAY
debug1: channel 2: new [X11 connection from 127.0.0.1 port 33086]
debug1: channel 3: read<=0 rfd 17 len 0
debug1: channel 3: read failed
debug1: channel 3: close_read
debug1: channel 3: input open -> drain
debug1: channel 3: ibuf empty
debug1: channel 3: send eof
debug1: channel 3: input drain -> closed
debug1: channel 2: open confirm rwindow 2097152 rmax 16384
debug1: channel 3: rcvd eof
debug1: channel 3: output open -> drain
debug1: channel 3: obuf empty
debug1: channel 3: close_write
debug1: channel 3: output drain -> closed
debug1: channel 3: rcvd close
debug1: channel 3: send close
debug1: channel 3: is dead
debug1: channel 3: garbage collecting
debug1: channel_free: channel 3: X11 connection from 127.0.0.1 port 33085, nchan nels 4

Após algum intervalo de tempo aleatório: a conexão é perdida:

Read error from remote host 10.0.2.2: Connection reset by peer
debug1: Calling cleanup 0x806d882(0x80afd90)
debug1: session_pty_cleanup: session 0 release /dev/pts/8
debug1: Calling cleanup 0x80729a7(0x0)
debug1: channel_free: channel 0: server-session, nchannels 3
debug1: channel_free: channel 1: X11 inet listener, nchannels 2
debug1: channel_free: channel 2: X11 connection from 127.0.0.1 port 33086, nchannels 1
debug1: Calling cleanup 0x8064fe7(0x80c1318)
debug1: Calling cleanup 0x807e79a(0x0)
debug1: compress outgoing: raw data 36410262, compressed 3980612, factor 0.11
debug1: compress incoming: raw data 18374832, compressed 674656, factor 0.04
monitor debug1: Monitor received SIGCHLD.

Saída do ssh recebido:

~> ssh [email protected] -p 2222
Connection to 127.0.0.1 closed by remote host.
Connection to 127.0.0.1 closed

Responder1

Existe um roteador NAT entre as duas máquinas? Pode estar fechando a conexão por inatividade e timeouts?

O cliente SSH pode ativar o KeepAlive no nível SSH para tentar evitar esse cenário.

Para o cliente openssh, incluímos o seguinte no arquivo de configuração do lado do cliente (/etc/ssh/ssh_config ou ~/.ssh/config):

KeepAlive sim

Responder2

Acabei de resolver uma situação semelhante a esta em uma caixa CentOS7. Acontece que a caixa de diálogo do comando 'nmtui' adicionou silenciosamente um '/32' ao final do nosso endereço IP estático. Isso mudou a máscara de rede para 255.255.255.255 e o IP de transmissão para o mesmo IP da interface. Isso resultou em um comportamento ARP muito incomum e causou muitas conexões perdidas. Execute um 'ifconfig -a' para verificar novamente suas configurações de máscara de rede e transmissão.

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