`debug1：client_input_global_request：rtype [email protected] Want_reply 0`でSSH接続が中断されます。

2024-06-23 • tag-icon

ssh

`debug1：client_input_global_request：rtype [email protected] Want_reply 0`でSSH接続が中断されます。

特定のコンピュータでSSHを使用すると、奇妙な動作が発生します。 SSH経由で接続すると数秒間動作し、「停止」します。詳細情報表示モードで新しいSSHを作成すると操作がssh -v中断され（シェルプロンプトが表示されない）、最終出力は次のようになります。

debug1: client_input_global_request: rtype [email protected] want_reply 0

その理由は何ですか？

完全なログ：

ssh -v [email protected]        
OpenSSH_7.9p1, OpenSSL 1.0.2r  26 Feb 2019
debug1: Reading configuration data /home/chris/.ssh/config
debug1: /home/chris/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 5: Applying options for *
debug1: auto-mux: Trying existing master
debug1: Control socket "/home/chris/.ssh/sockets/[email protected]" does not exist
debug1: Connecting to 192.168.0.37 [192.168.0.37] port 22.
debug1: Connection established.
debug1: identity file /home/chris/.ssh/id_rsa type 0
debug1: identity file /home/chris/.ssh/id_rsa-cert type -1
debug1: identity file /home/chris/.ssh/id_dsa type -1
debug1: identity file /home/chris/.ssh/id_dsa-cert type -1
debug1: identity file /home/chris/.ssh/id_ecdsa type -1
debug1: identity file /home/chris/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/chris/.ssh/id_ed25519 type -1
debug1: identity file /home/chris/.ssh/id_ed25519-cert type -1
debug1: identity file /home/chris/.ssh/id_xmss type -1
debug1: identity file /home/chris/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.9
debug1: match: OpenSSH_7.9 pat OpenSSH* compat 0x04000000
debug1: Authenticating to 192.168.0.37:22 as 'chris'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: [email protected]
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-ed25519 SHA256:Q3IPnF5PorgEAJwAF1EBlFrD4XmttrmsSBgVQKvgaUM
debug1: Host '192.168.0.37' is known and matches the ED25519 host key.
debug1: Found key in /home/chris/.ssh/known_hosts:54
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: Will attempt key: /home/chris/.ssh/id_rsa RSA SHA256:jZ4wVcWhhtqNdX/SwnrbG7TRfTE9cmm9Ar1PLyCJwuc
debug1: Will attempt key: /home/chris/.ssh/id_dsa 
debug1: Will attempt key: /home/chris/.ssh/id_ecdsa 
debug1: Will attempt key: /home/chris/.ssh/id_ed25519 
debug1: Will attempt key: /home/chris/.ssh/id_xmss 
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,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Offering public key: /home/chris/.ssh/id_rsa RSA SHA256:jZ4wVcWhhtqNdX/SwnrbG7TRfTE9cmm9Ar1PLyCJwuc
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Trying private key: /home/chris/.ssh/id_dsa
debug1: Trying private key: /home/chris/.ssh/id_ecdsa
debug1: Trying private key: /home/chris/.ssh/id_ed25519
debug1: Trying private key: /home/chris/.ssh/id_xmss
debug1: Next authentication method: keyboard-interactive
Password: 
debug1: Authentications that can continue: publickey,password,keyboard-interactive
Password: 
debug1: Authentication succeeded (keyboard-interactive).
Authenticated to 192.168.0.37 ([192.168.0.37]:22).
debug1: setting up multiplex master socket
debug1: channel 0: new [/home/chris/.ssh/sockets/[email protected]]
debug1: control_persist_detach: backgrounding master process
debug1: forking to background
debug1: Entering interactive session.
debug1: pledge: id
debug1: multiplexing control connection
debug1: channel 1: new [mux-control]
debug1: channel 2: new [client-session]
debug1: client_input_global_request: rtype [email protected] want_reply 0

この問題はここでも発生したようですが、具体的な回避策は記載されていません。

https://forum.manjaro.org/t/ssh-connection-hangs-after-logging-in/4847/28 https://stackoverflow.com/questions/53410559/ssh-stuck-to-client-input-global-request-rtype-hostkeys-00openssh-com-want-rep

奇妙なことに、これはネットワークの問題のようです。しかし、それ以外はすべてうまくいきます...奇妙に見えます。

SSHシェル/接続が中断されるたびにTCP Retransmissionネットワークログに表示されます。

問題のマシンに接続するために使用している他のマシンのtshark出力は次のとおりです。

sudo tshark -f "tcp port 22" -i any   
Running as user "root" and group "root". This could be dangerous.
tshark: Lua: Error during loading:
 ...94ln7cy52ca-wireshark-cli-2.6.6/share/wireshark/init.lua:32: dofile has been disabled due to running Wireshark as superuser. See https://wiki.wireshark.org/CaptureSetup/CapturePrivileges for help in running Wireshark as an unprivileged user.
Capturing on 'any'
    1 0.000000000  192.168.0.6 → 192.168.0.37 SSH 128 Client: Encrypted packet (len=60)
    2 4.393384377  192.168.0.6 → 192.168.0.37 TCP 76 33764 → 22 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 TSval=4094028584 TSecr=0 WS=128
    3 4.451072834 192.168.0.37 → 192.168.0.6  TCP 76 22 → 33764 [SYN, ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=2514759161 TSecr=4094028584 WS=128
    4 4.451117228  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=1 Ack=1 Win=64256 Len=0 TSval=4094028641 TSecr=2514759161
    5 4.451358744  192.168.0.6 → 192.168.0.37 SSH 89 Client: Protocol (SSH-2.0-OpenSSH_7.9)
    6 4.459998058 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=1 Ack=22 Win=65152 Len=0 TSval=2514759170 TSecr=4094028641
    7 4.475179826 192.168.0.37 → 192.168.0.6  SSHv2 89 Server: Protocol (SSH-2.0-OpenSSH_7.9)
    8 4.475220883  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=22 Ack=22 Win=64256 Len=0 TSval=4094028665 TSecr=2514759186
    9 4.475398990  192.168.0.6 → 192.168.0.37 SSHv2 1468 Client: Key Exchange Init
   10 4.486180419 192.168.0.37 → 192.168.0.6  SSHv2 780 Server: Key Exchange Init
   11 4.486193334  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=1422 Ack=734 Win=64128 Len=0 TSval=4094028676 TSecr=2514759194
   12 4.488140621 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=734 Ack=1422 Win=64128 Len=0 TSval=2514759196 TSecr=4094028666
   13 4.488149618  192.168.0.6 → 192.168.0.37 SSHv2 116 Client: Elliptic Curve Diffie-Hellman Key Exchange Init
   14 4.495305110 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=734 Ack=1470 Win=64128 Len=0 TSval=2514759206 TSecr=4094028678
   15 4.591438906 192.168.0.37 → 192.168.0.6  SSHv2 448 Server: Elliptic Curve Diffie-Hellman Key Exchange Reply, New Keys, Encrypted packet (len=172)
   16 4.591486757  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=1470 Ack=1114 Win=64128 Len=0 TSval=4094028782 TSecr=2514759301
   17 4.598789938  192.168.0.6 → 192.168.0.37 SSHv2 84 Client: New Keys
   18 4.605412113 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=1114 Ack=1486 Win=64128 Len=0 TSval=2514759316 TSecr=4094028789
   19 4.605456186  192.168.0.6 → 192.168.0.37 SSHv2 112 Client: Encrypted packet (len=44)
   20 4.611308177 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=1114 Ack=1530 Win=64128 Len=0 TSval=2514759322 TSecr=4094028796
   21 4.611946582 192.168.0.37 → 192.168.0.6  SSHv2 112 Server: Encrypted packet (len=44)
   22 4.611986097  192.168.0.6 → 192.168.0.37 SSHv2 136 Client: Encrypted packet (len=68)
   23 4.617575973 192.168.0.37 → 192.168.0.6  TCP 68 22 → 33764 [ACK] Seq=1158 Ack=1598 Win=64128 Len=0 TSval=2514759328 TSecr=4094028802
   24 4.625638737 192.168.0.37 → 192.168.0.6  SSHv2 144 Server: Encrypted packet (len=76)
   25 4.625769093  192.168.0.6 → 192.168.0.37 SSHv2 696 Client: Encrypted packet (len=628)
   26 4.646837769 192.168.0.37 → 192.168.0.6  SSHv2 144 Server: Encrypted packet (len=76)
   27 4.646955832  192.168.0.6 → 192.168.0.37 SSHv2 160 Client: Encrypted packet (len=92)
   28 4.663613579 192.168.0.37 → 192.168.0.6  SSHv2 128 Server: Encrypted packet (len=60)
   29 4.704685867  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=2318 Ack=1370 Win=64128 Len=0 TSval=4094028895 TSecr=2514759374
   30 6.314404352  192.168.0.6 → 192.168.0.37 SSHv2 152 Client: Encrypted packet (len=84)
   31 6.408675360 192.168.0.37 → 192.168.0.6  SSHv2 112 Server: Encrypted packet (len=44)
   32 6.408721657  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=2402 Ack=1414 Win=64128 Len=0 TSval=4094030599 TSecr=2514761119
   33 6.408792972  192.168.0.6 → 192.168.0.37 SSHv2 152 Client: Encrypted packet (len=84)
   34 6.417718667 192.168.0.37 → 192.168.0.6  SSHv2 96 Server: Encrypted packet (len=28)
   35 6.417766608  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=2486 Ack=1442 Win=64128 Len=0 TSval=4094030608 TSecr=2514761128
   36 6.417913946  192.168.0.6 → 192.168.0.37 SSHv2 180 Client: Encrypted packet (len=112)
   37 6.433295532 192.168.0.37 → 192.168.0.6  SSHv2 720 Server: Encrypted packet (len=652)
   38 6.433347530  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=2598 Ack=2094 Win=64128 Len=0 TSval=4094030624 TSecr=2514761143
   39 6.440019259 192.168.0.37 → 192.168.0.6  SSHv2 112 Server: Encrypted packet (len=44)
   40 6.440039427  192.168.0.6 → 192.168.0.37 TCP 68 33764 → 22 [ACK] Seq=2598 Ack=2138 Win=64128 Len=0 TSval=4094030630 TSecr=2514761150
   41 6.440138534  192.168.0.6 → 192.168.0.37 SSHv2 460 Client: Encrypted packet (len=392)
   42 6.674368565  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094030865 TSecr=2514761150
   43 6.907359347  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094031098 TSecr=2514761150
   44 7.370357846  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094031561 TSecr=2514761150
   45 8.330683518  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094032521 TSecr=2514761150
   46 10.186372155  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094034377 TSecr=2514761150
   47 13.898356243  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094038089 TSecr=2514761150
   48 19.274398519  192.168.0.6 → 192.168.0.37 TCP 520 [TCP Retransmission] 33742 → 22 [FIN, PSH, ACK] Seq=4294966905 Ack=1 Win=501 Len=452 TSval=4094043465 TSecr=2514723303
   49 21.322527112  192.168.0.6 → 192.168.0.37 TCP 460 [TCP Retransmission] 33764 → 22 [PSH, ACK] Seq=2598 Ack=2138 Win=64128 Len=392 TSval=4094045513 TSecr=2514761150

ベストアンサー1

SSHサーバーでいくつかのネットワーク構成を変更した後も同じ問題が発生しました。私の場合、TCPの再送信は、クライアントがサーバーから応答を受け取らず、同じパケットを再送信しようとしたことを示します。同時に、サーバーはパケットを受信し、サーバーのネットワークトレースは応答が送信されていることを示すようです。

私の場合の基本的な問題は、サーバーのネットワークインターフェースに誤ったCIDRプレフィックス（a）があることでし/32た/24。この場合、サーバーからのパケットをクライアントに再ルーティングすることはできません。

問題はnetcatを介して再現できます。サーバーでsshd一般的なデーモンを終了します。

nc -l 22

クライアント側から：

nc sshserver 22

その後、クライアントnetcatに数行のテキストを入力した後、クライアントからサーバーに送信された最初の行が「成功」したが、後続の行がないことを確認しました。ネットワークトレースはまったく同じ動作を示します。クライアントは、データの最初の行を含む最初のパケットの「TCP再送」を確認し続け、その後のデータは「中断」します。

ネットワーク構成を変更すると、SSHも修正されました。

ベストアンサー1

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