scp“丢失连接”但 ssh 工作正常

Question

我可以通过 ssh 进入的服务器已经开始拒绝 scp。

$ scp ~/tmp/foo user@some.example.com:~/tmp/
lost connection

随着scp -v -v我可以看到连接成功和转移看似成功，但没有文件出现在另一边。

OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /Users/schwern/.ssh/config
debug1: /Users/schwern/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to testcurrent01.dev.liquidweb.com [10.30.152.254] port 22.
debug1: Connection established.
debug1: identity file /Users/schwern/.ssh/id_rsa type -1
debug1: identity file /Users/schwern/.ssh/id_rsa-cert type -1
debug1: identity file /Users/schwern/.ssh/id_dsa type -1
debug1: identity file /Users/schwern/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
...lots of authentication details...
debug1: Enabling compression at level 6.
debug1: Authentication succeeded (publickey).
Authenticated to user@some.example.com ([1.2.3.4]:22).
debug2: fd 5 setting O_NONBLOCK
debug2: fd 6 setting O_NONBLOCK
debug1: channel 0: new [client-session]
debug2: channel 0: send open
debug1: Entering interactive session.
debug2: callback start
debug2: client_session2_setup: id 0
debug2: fd 3 setting TCP_NODELAY
debug1: Sending environment.
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending command: scp -v -t -- ~/tmp/
debug2: channel 0: request exec confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: exec request accepted on channel 0
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug2: channel 0: rcvd close
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
debug1: fd 0 clearing O_NONBLOCK
debug1: fd 1 clearing O_NONBLOCK
Transferred: sent 4576, received 2520 bytes, in 0.0 seconds
Bytes per second: sent 167737.0, received 92372.6
debug1: Exit status 0
debug1: compress outgoing: raw data 135, compressed 121, factor 0.90
debug1: compress incoming: raw data 66, compressed 52, factor 0.79
lost connection

它是一台 CentOS 5.9 机器。

我检查过的东西...

• 我有权写入该目录。
• 用户有一个合理的外壳（/bin/bash）。
• 我试着把我~/.ssh/config的路移开。
• 从其他操作系统完全不同的机器 scp 到该机器也会失败。
• 磁盘未满。
• 重新启动 sshd。

/var/log/secure 包含...

Apr  4 14:23:22 some sshd[12576]: Postponed publickey for user from 1.2.3.4 port 33581 ssh2
Apr  4 14:23:22 some sshd[12575]: Accepted publickey for user from 1.2.3.4 port 33581 ssh2
Apr  4 14:23:22 some sshd[12575]: pam_unix(sshd:session): session opened for user user by (uid=0)
Apr  4 14:23:22 some sshd[12575]: pam_unix(sshd:session): session closed for user user

接下来我可以检查什么？

Answer 1

scp通过ssh连接到远程主机，然后scp在该主机上启动程序的另一个副本来工作。两个 scp 实例通过 ssh 连接进行通信以执行文件传输。

scp当 ssh 连接过早断开时，本地程序会打印“丢失的连接” 。通常的原因是scp远程主机上的程序要么无法启动，要么过早退出。这可能是因为远程主机上不存在 scp 程序，或者它不在您的命令 PATH 中，或者它没有标记为可执行文件，或者它在启动后崩溃，或者类似的东西。

Answer 2

有同样的问题。

如果您对 Centos 进行了最小安装，它只会安装openssh和openssh-server包，而不安装openssh-clients. sudo yum install openssh-clients将解决您的问题。