我无法通过 SSH 连接到我的 Pi B。输入密码后，shell 就挂起了 - 没有错误消息，pi 上也没有提示。无法用Ctrl+C任何方法终止 ssh。
对 pi 执行 ping 操作成功，pi 本身也运行良好。尝试从运行 debian jessie 的笔记本电脑进行连接，还尝试从 Android 手机使用 JuiceSSH。所有设备都在同一个 LAN 中。
我可以通过重启 pi 来解决这个问题，但几天后（我还没有找到具体的时间范围），同样的问题又出现了。这似乎与这个帖子从 2 年前开始，因为客户端登录会挂起相同的命令并显示相同的特征。唯一建议的修复方法（除了重新启动）没有帮助。
这个帖子似乎描述了相同的问题，但原因不同。他甚至没有得到密码提示。大多数评论都表明客户端存在问题或未启用 ssh。但这里不是这两种情况，因为我可以在重启后建立 ssh 连接，而无需在客户端进行任何更改。
这是客户端的输出：ssh -vvv [email protected]
chris@chris-laptop:~$ ssh -vvv [email protected]
OpenSSH_6.7p1 Debian-5, OpenSSL 1.0.1k 8 Jan 2015
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.0.20 [192.168.0.20] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.7p1 Debian-5
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.0p1 Debian-4+deb7u2
debug1: match: OpenSSH_6.0p1 Debian-4+deb7u2 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "192.168.0.20" from file "/home/chris/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /home/chris/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],[email protected],ssh-ed25519,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],[email protected],arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],[email protected],arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1,[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1,[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: setup [email protected]
debug1: kex: server->client aes128-ctr [email protected] none
debug2: mac_setup: setup [email protected]
debug1: kex: client->server aes128-ctr [email protected] none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ECDSA f2:ff:64:a7:06:a5:b7:16:0c:b8:5a:f8:62:18:39:21
debug3: load_hostkeys: loading entries for host "192.168.0.20" from file "/home/chris/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /home/chris/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug1: Host '192.168.0.20' is known and matches the ECDSA host key.
debug1: Found key in /home/chris/.ssh/known_hosts:1
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/chris/.ssh/id_rsa ((nil)),
debug2: key: /home/chris/.ssh/id_dsa ((nil)),
debug2: key: /home/chris/.ssh/id_ecdsa ((nil)),
debug2: key: /home/chris/.ssh/id_ed25519 ((nil)),
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/chris/.ssh/id_rsa
debug3: no such identity: /home/chris/.ssh/id_rsa: No such file or directory
debug1: Trying private key: /home/chris/.ssh/id_dsa
debug3: no such identity: /home/chris/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/chris/.ssh/id_ecdsa
debug3: no such identity: /home/chris/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/chris/.ssh/id_ed25519
debug3: no such identity: /home/chris/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
[email protected]'s password:
debug2: we sent a password packet, wait for reply
debug1: Authentication succeeded (password).
Authenticated to 192.168.0.20 ([192.168.0.20]:22).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug1: Sending environment.
debug3: Ignored env XDG_VTNR
debug3: Ignored env SSH_AGENT_PID
debug3: Ignored env XDG_SESSION_ID
debug3: Ignored env GPG_AGENT_INFO
debug3: Ignored env TERM
debug3: Ignored env SHELL
debug3: Ignored env XDG_MENU_PREFIX
debug3: Ignored env VTE_VERSION
debug3: Ignored env GJS_DEBUG_OUTPUT
debug3: Ignored env WINDOWID
debug3: Ignored env GJS_DEBUG_TOPICS
debug3: Ignored env USER
debug3: Ignored env LS_COLORS
debug3: Ignored env SSH_AUTH_SOCK
debug3: Ignored env SESSION_MANAGER
debug3: Ignored env USERNAME
debug3: Ignored env PATH
debug3: Ignored env DESKTOP_SESSION
debug3: Ignored env PWD
debug1: Sending env LANG = de_DE.UTF-8
debug2: channel 0: request env confirm 0
debug3: Ignored env GDM_LANG
debug3: Ignored env GDMSESSION
debug3: Ignored env SHLVL
debug3: Ignored env XDG_SEAT
debug3: Ignored env HOME
debug3: Ignored env GNOME_DESKTOP_SESSION_ID
debug3: Ignored env XDG_SESSION_DESKTOP
debug3: Ignored env LOGNAME
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
debug3: Ignored env WINDOWPATH
debug3: Ignored env XDG_RUNTIME_DIR
debug3: Ignored env DISPLAY
debug3: Ignored env XDG_CURRENT_DESKTOP
debug3: Ignored env XAUTHORITY
debug3: Ignored env _
debug2: channel 0: request shell confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
摘录自 /var/log/auth.log：
Sep 2 17:14:30 pi-fp3k sshd[6595]: Accepted password for pi from 192.168.0.94 port 58653 ssh2
Sep 2 17:14:30 pi-fp3k sshd[6595]: pam_unix(sshd:session): session opened for user pi by (uid=0)
在此之前和之后只有 cronjobs，这很有趣，因为我当时尝试从不同的设备多次连接，但都显示挂起。
我还检查了 24 小时内的内存使用情况，发现有 300MB 以上的 RAM 一直可用。这是我所期望的，因为 pi 上运行的仅有的两个用户程序不应该生成足够的数据来填满 512MB 的 RAM。
编辑：我不知道发生了什么变化，但 ssh 连接已经好久没有断掉了。这实际上不是解决这个问题的办法，所以我就不讨论这个问题了。
答案1
我会将 RPi 直接（交叉）电缆与我的电脑或笔记本电脑连接起来，然后使用 wireshark/tcpdump 来分析网络流量，您肯定会看到问题出在哪里。
如果不在应用程序级别，也可以尝试从 RPi 本地连接到 ssh。这样，您可以调试它是否与网络或应用程序相关。