SSH 连接挂在 `debug1: client_input_global_request: rtype [email protected] Want_reply 0` 上

2024-6-4 • tag-icon

SSH 连接挂在 `debug1: client_input_global_request: rtype [email protected] Want_reply 0` 上

我在一台特定机器上使用 SSH 时出现了这种奇怪的行为。如果我通过 SSH 连接到它，它会工作几秒钟，然后就“挂起”。我可以以详细方式创建一个新的 SSH ssh -v，它只会挂起（不会显示 shell 提示符），最后输出如下：

debug1: client_input_global_request: rtype [email protected] want_reply 0

造成这种情况的原因可能是什么？

完整日志：

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

看来这里也遇到了这个问题，但是没有提到具体的解决方案：

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

奇怪的是，这似乎是一个网络问题 - 但除此之外一切正常......这看起来很奇怪。

每次 SSH shell/连接挂起时，我都会TCP Retransmission在网络日志中看到。

这是我用来连接到相关机器的另一台机器的 tshark 输出：

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

答案1

在修改 ssh 服务器上的一些网络配置后，我遇到了同样的问题。在我的例子中，TCP 重传表明客户端没有从服务器收到任何响应，并且正在尝试重新发送相同的数据包。与此同时，服务器收到了该数据包，并且服务器上的网络跟踪似乎表明正在发送响应。

就我而言，根本问题是服务器上网络接口的 CIDR 前缀无效 - a/32而不是/24.鉴于此，来自服务器的数据包无法路由回客户端。

这个问题可以通过 netcat 重现：在服务器上sshd关闭通常的守护进程：

nc -l 22

在客户端：

nc sshserver 22

然后在客户端 netcat 中输入几行文本后，注意到从客户端发送的第一行“成功”到服务器，但没有后续行。网络跟踪显示完全相同的行为：客户端继续看到包含第一行数据的第一个数据包的“TCP 重传”，而后续数据被“卡住”。

修复网络配置也修复了 ssh。

答案2

许多年前，在一台特定的机器上出现过ssh类似错误，因此在这里提及这种情况似乎是个好主意，这种情况也可能是由于主机服务器的用户会话登录脚本中发出文本的某些内容（例如命令）引起的echo。或在某些情况下.bashrc输出调用的程序。stderr

答案1

答案2

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