我正在尝试通过 sftp 连接到运行 sftp 服务器的 Synology NAS 215j。sshd 对 root 用户来说非常有效，但是当我以 root 身份执行 sftp 时，我Connection closed输入正确的 ssh 密钥密码后就出现了问题。
这里是在 /etc/ssh/sshd_config 中：
Ciphers blowfish-cbc,aes256-cbc,aes256-ctr,aes128-ctr,[email protected],aes192-ctr,[email protected],[email protected],
KexAlgorithms [email protected],diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
MACs hmac-sha1,hmac-sha2-256,hmac-sha2-512,[email protected],[email protected],[email protected],[email protected]
Protocol 2
SyslogFacility AUTHPRIV
LogLevel ERROR
LoginGraceTime 60
MaxStartups 2
MaxAuthTries 3
MaxSessions 3
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile %h/.ssh/authorized_keys
RhostsRSAAuthentication no
IgnoreRhosts yes
ChallengeResponseAuthentication no
UsePAM no
PasswordAuthentication no
PermitEmptyPasswords no
PermitRootLogin without-password
TCPKeepAlive yes
ClientAliveInterval 600
ClientAliveCountMax 0
Banner /etc/ssh/issue.net
AllowTcpForwarding no
X11Forwarding no
UsePrivilegeSeparation sandbox
AcceptEnv LANG LC_*
UseDNS no
ChrootDirectory none
Subsystem sftp internal-sftp -f DAEMON -u 000
Match User root
AllowTcpForwarding yes
以下是详细输出：
$ sftp -P 22221 -vvv root@nas
OpenSSH_7.1p1, OpenSSL 1.0.2e 3 Dec 2015
debug1: Reading configuration data /usr/local/etc/ssh/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to nas [192.168.1.51] port 22221.
debug1: Connection established.
debug1: identity file /Users/drewshg312/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/drewshg312/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6p2-hpn14v4
debug1: match: OpenSSH_6.6p2-hpn14v4 pat OpenSSH_6.5*,OpenSSH_6.6* compat 0x14000000
debug2: fd 5 setting O_NONBLOCK
debug1: Authenticating to nas:22221 as 'root'
debug2: compat_kex_proposal: original KEX proposal: [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
debug2: Compat: skipping algorithm "[email protected]"
debug2: compat_kex_proposal: compat KEX proposal: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
debug3: put_host_port: [nas]:22221
debug3: hostkeys_foreach: reading file "/Users/drewshg312/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/drewshg312/.ssh/known_hosts:10
debug3: load_hostkeys: loaded 1 keys from [nas]:22221
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: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],ssh-ed25519,ssh-rsa
debug2: kex_parse_kexinit: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[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],aes128-ctr,aes192-ctr,aes256-ctr,[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: [email protected],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: blowfish-cbc,aes256-cbc,aes256-ctr,aes128-ctr,[email protected],aes192-ctr,[email protected],[email protected],
debug2: kex_parse_kexinit: blowfish-cbc,aes256-cbc,aes256-ctr,aes128-ctr,[email protected],aes192-ctr,[email protected],[email protected],
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha2-256,hmac-sha2-512,[email protected],[email protected],[email protected],[email protected]
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha2-256,hmac-sha2-512,[email protected],[email protected],[email protected],[email protected]
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
debug1: kex: server->client [email protected] <implicit> none
debug1: kex: client->server [email protected] <implicit> none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<8192<8192) sent
debug1: got SSH2_MSG_KEX_DH_GEX_GROUP
debug2: bits set: 1041/2048
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: got SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:SkJiuE7k6Z2ooVXv2cb4PGTeXgh+xNjxMtDG+8Pfqw0
debug3: put_host_port: [192.168.1.51]:22221
debug3: put_host_port: [nas]:22221
debug3: hostkeys_foreach: reading file "/Users/drewshg312/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/drewshg312/.ssh/known_hosts:10
debug3: load_hostkeys: loaded 1 keys from [nas]:22221
debug3: hostkeys_foreach: reading file "/Users/drewshg312/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/drewshg312/.ssh/known_hosts:10
debug3: load_hostkeys: loaded 1 keys from [192.168.1.51]:22221
debug1: Host '[nas]:22221' is known and matches the ECDSA host key.
debug1: Found key in /Users/drewshg312/.ssh/known_hosts:10
debug2: bits set: 1039/2048
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
debug1: pubkey_prepare: ssh_get_authentication_socket: Connection refused
debug2: key: /Users/drewshg312/.ssh/id_rsa (0x7f97fc000610),
debug2: key: /Users/drewshg312/.ssh/id_dsa (0x0),
debug2: key: /Users/drewshg312/.ssh/id_ecdsa (0x0),
debug2: key: /Users/drewshg312/.ssh/id_ed25519 (0x0),
debug3: input_userauth_banner
) ( ) )
( * ) * ) ( /( * ))\ ) ( /( ( /(
)\ ` ) /(` ) /(( )\())` ) /(()/( )\()) )\())
((((_)( ( )(_))( )(_))\ ((_)\ ( )(_))(_)|(_)\ ((_)\
)\ _ )\(_(_())(_(_()|(_) _((_)(_(_()|_)) ((_) _((_)
(_)_\(_)_ _||_ _| __| \| ||_ _|_ _| / _ \| \| |
/ _ \ | | | | | _|| .` | | | | | | (_) | .` |
/_/ \_\ |_| |_| |___|_|\_| |_| |___| \___/|_|\_|
UNAUTHORIZED ACCESS TO THIS SYSTEM IS FORBIDDEN AND WILL BE
PROSECUTED BY LAW!
DISCONNECT IMMIDIATELY IF YOU ARE NOT AUTHORIZED PERSON!
By accessing this system you agree that all your actions
will be monitored and logged.
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred 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: Offering RSA public key: /Users/drewshg312/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 535
debug2: input_userauth_pk_ok: fp SHA256:NWHiMGnH1Sz8K/cLRV9x493V6B6P8+oat6xtwFViZl4
debug3: sign_and_send_pubkey: RSA SHA256:NWHiMGnH1Sz8K/cLRV9x493V6B6P8+oat6xtwFViZl4
Enter passphrase for key '/Users/drewshg312/.ssh/id_rsa':
debug1: Authentication succeeded (publickey).
Authenticated to nas ([192.168.1.51]:22221).
debug2: fd 6 setting O_NONBLOCK
debug3: fd 7 is O_NONBLOCK
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 5 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x08
debug2: client_session2_setup: id 0
debug1: Sending subsystem: sftp
debug2: channel 0: request subsystem confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 87380
debug2: channel_input_status_confirm: type 99 id 0
debug2: subsystem 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
debug1: client_input_channel_req: channel 0 rtype [email protected] reply 0
debug2: channel 0: rcvd eow
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug2: channel 0: rcvd close
debug3: channel 0: will not send data after close
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
debug3: channel 0: status: The following connections are open:
#0 client-session (t4 r0 i3/0 o3/0 fd -1/-1 cc -1)
debug1: fd 0 clearing O_NONBLOCK
debug3: fd 1 is not O_NONBLOCK
Transferred: sent 4144, received 3136 bytes, in 0.2 seconds
Bytes per second: sent 24522.5, received 18557.5
debug1: Exit status 255
Connection closed
请帮忙！我很确定我的 sshd 配置中有一些我不完全理解的地方……我需要有人指出我的错误
谢谢
更新：
以下是我从中获得的日志信息grep -i sftp /var/log/*：
/var/log/synoinfo.conf.bad:sftpPort="22"
/var/log/synoservice.log:Dec 5 12:54:25 nas-server entry.cgi_SYNO.Core.User.Home[1].set[9165]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 5 12:54:25 nas-server entry.cgi_SYNO.Core.User.Home[1].set[9165]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 5 12:54:25 nas-server entry.cgi_SYNO.Core.User.Home[1].set[9165]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 5 21:58:25 nas-server entry.cgi_SYNO.Core.Upgrade[1].start[22749]: service_pause_by_reason.c:27 synoservice: pause [sftp] by reason [smallupdate] ...
/var/log/synoservice.log:Dec 5 21:58:25 nas-server entry.cgi_SYNO.Core.Upgrade[1].start[22749]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 5 21:58:25 nas-server entry.cgi_SYNO.Core.Upgrade[1].start[22749]: service_pause.c:48 synoservice: [sftp] is already disable/pause.
/var/log/synoservice.log:Dec 5 21:58:25 nas-server entry.cgi_SYNO.Core.Upgrade[1].start[22749]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 12 19:56:27 nas entry.cgi_SYNO.Core.User.Home[1].set[16689]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 12 19:56:27 nas entry.cgi_SYNO.Core.User.Home[1].set[16689]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 12 19:56:27 nas entry.cgi_SYNO.Core.User.Home[1].set[16689]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 14 14:09:02 nas entry.cgi_SYNO.Core.User.Home[1].set[27314]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 14 14:09:02 nas entry.cgi_SYNO.Core.User.Home[1].set[27314]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 14 14:09:02 nas entry.cgi_SYNO.Core.User.Home[1].set[27314]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 14 14:10:39 nas entry.cgi_SYNO.Core.User.Home[1].set[27623]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 14 14:10:39 nas entry.cgi_SYNO.Core.User.Home[1].set[27623]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 14 14:10:39 nas entry.cgi_SYNO.Core.User.Home[1].set[27623]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 15 18:00:53 nas entry.cgi_SYNO.Core.User.Home[1].set[13303]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 15 18:00:53 nas entry.cgi_SYNO.Core.User.Home[1].set[13303]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 15 18:00:53 nas entry.cgi_SYNO.Core.User.Home[1].set[13303]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 15 18:05:03 nas entry.cgi_SYNO.Core.User.Home[1].set[14018]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 15 18:05:03 nas entry.cgi_SYNO.Core.User.Home[1].set[14018]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 15 18:05:03 nas entry.cgi_SYNO.Core.User.Home[1].set[14018]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 17 19:42:01 nas entry.cgi_SYNO.Core.BandwidthControl.Protocol[1].set[12255]: service_reload.c:33 synoservice: reload [sftp].
/var/log/synoservice.log:Dec 17 19:42:01 nas entry.cgi_SYNO.Core.BandwidthControl.Protocol[1].set[12255]: service_reload.c:40 synoservice: [sftp] is not enabled, skip reload action
/var/log/synoservice.log:Dec 17 19:42:01 nas entry.cgi_SYNO.Core.BandwidthControl.Protocol[1].set[12255]: service_reload.c:53 synoservice: finish reload [sftp].
/var/log/synoservice.log:Dec 17 21:29:43 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[17732]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 21:29:45 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[17732]: service_start.c:206 synoservice: [sftp] started.
/var/log/synoservice.log:Dec 17 21:32:06 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18453]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 17 21:32:08 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18453]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 17 21:32:10 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18453]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 21:32:12 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18453]: service_start.c:206 synoservice: [sftp] started.
/var/log/synoservice.log:Dec 17 21:32:51 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18960]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 17 21:32:52 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18960]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 17 21:32:55 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18960]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 21:32:56 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[18960]: service_start.c:206 synoservice: [sftp] started.
/var/log/synoservice.log:Dec 17 21:38:47 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[19744]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 17 21:38:48 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[19744]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 17 21:38:50 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[19744]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 21:38:52 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[19744]: service_start.c:206 synoservice: [sftp] started.
/var/log/synoservice.log:Dec 17 21:40:09 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[20292]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 17 21:40:11 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[20292]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 17 21:40:13 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[20292]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 21:40:14 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[20292]: service_start.c:206 synoservice: [sftp] started.
/var/log/synoservice.log:Dec 17 22:14:56 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22807]: service_pause.c:39 synoservice: [sftp] pausing ...
/var/log/synoservice.log:Dec 17 22:14:58 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22807]: service_pause.c:89 synoservice: [sftp] paused.
/var/log/synoservice.log:Dec 17 22:14:58 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22807]: service_stop.c:49 synoservice: [sftp] stopping ...
/var/log/synoservice.log:Dec 17 22:15:00 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22807]: service_stop.c:106 synoservice: [sftp] stopped.
/var/log/synoservice.log:Dec 17 22:15:02 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22990]: service_start.c:108 synoservice: [sftp] starting ...
/var/log/synoservice.log:Dec 17 22:15:03 nas entry.cgi_SYNO.Core.FileServ.FTP.SFTP[1].set[22990]: service_start.c:206 synoservice: [sftp] started.
答案1
看起来服务器端有问题。只要您请求 SFTP 子系统，您就会收到文件结束符，并以 255 退出。
debug2: subsystem request accepted on channel 0
debug2: channel 0: rcvd eof
...
debug1: Exit status 255
你能检查一下服务器上的日志吗？可能在 /var/log/ 中 grep
grep -i sftp /var/log/*
应该返回一些有用的内容。