我遇到了一种奇怪的情况，但一直无法确定根本原因。我有一个需要通过 SFTP 连接到互联网的服务。通过 SFTP 连接时，我在调试模式下运行时看到的内容如下：
[user1@localhost-live ~]$ sftp -oIdentityFile=~/.ssh/privatekey -oPort=4321 -vvv [email protected]
OpenSSH_7.9p1, OpenSSL 1.1.1b FIPS 26 Feb 2019
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 52: Including file /etc/ssh/ssh_config.d/05-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug2: checking match for 'final all' host 1.2.3.4 originally 1.2.3.4
debug3: /etc/ssh/ssh_config.d/05-redhat.conf line 3: not matched 'final'
debug2: match not found
debug3: /etc/ssh/ssh_config.d/05-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1 (parse only)
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-gex-sha1-,gss-group14-sha1-,gss-group1-sha1-]
debug3: kex names ok: [[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1]
debug1: configuration requests final Match pass
debug2: resolve_canonicalize: hostname 1.2.3.4 is address
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 52: Including file /etc/ssh/ssh_config.d/05-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug2: checking match for 'final all' host 1.2.3.4 originally 1.2.3.4
debug3: /etc/ssh/ssh_config.d/05-redhat.conf line 3: matched 'final'
debug2: match found
debug3: /etc/ssh/ssh_config.d/05-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-gex-sha1-,gss-group14-sha1-,gss-group1-sha1-]
debug3: kex names ok: [[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1]
debug2: ssh_connect_direct
debug1: Connecting to 1.2.3.4 [1.2.3.4] port 4321.
debug1: Connection established.
debug1: identity file /home/user1/.ssh/privatekey type -1
debug1: identity file /home/user1/.ssh/privatekey-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9
如您所见，连接已建立，我的系统提供了私钥，但在输入“本地版本字符串 SSH-2.0-OpenSSH_7.9”后，客户端和服务器就停止通信了。服务器不会断开连接，或者继续运行。它只是卡住了。
我认为问题可能与 OpenSSH 或 OpenSSL 的版本有关。但似乎都不是。我在客户端运行的是 OpenSSH 7.9p1 和 OpenSSL 1.1.1b。另一端的服务器运行的是以下设置：
# override default of no subsystems
Subsystem sftp internal-sftp
# sftp only on port 4321 (it's exposed to internet)
Match LocalPort 4321
ForceCommand internal-sftp
X11Forwarding no
AllowTCPForwarding no
ChrootDirectory /mnt/efs/sftp/%u
这是在 Red Hat 7.4 上运行的 OpenSSH_7.4p1、OpenSSL 1.0.2k-fips。
奇怪的是，我在上面这个例子中使用的客户端是 Fedora 30 版本，并且它非常接近前沿技术。
我在我的机器上本地运行 Manjaro Linux，当我尝试连接到同一系统时，结果不同。我在那里运行的版本是 OpenSSH_8.0p1 和 OpenSSL 1.1.1b。我可以毫无问题地连接。以下是输出；
[user1@user1-m380 ~]$ sftp -oIdentityFile=~/.ssh/privatekey -oPort=4321 -vvv [email protected]
OpenSSH_8.0p1, OpenSSL 1.1.1b 26 Feb 2019
debug1: Reading configuration data /home/user1/.ssh/config
debug1: /home/user1/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: resolve_canonicalize: hostname 1.2.3.4 is address
debug2: ssh_connect_direct
debug1: Connecting to 1.2.3.4 [1.2.3.4] port 4321.
debug1: Connection established.
debug1: identity file /home/user1/.ssh/privatekey type -1
debug1: identity file /home/user1/.ssh/privatekey-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.0
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 1.2.3.4:4321 as 'user1'
debug3: put_host_port: [1.2.3.4]:4321
debug3: hostkeys_foreach: reading file "/home/user1/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/user1/.ssh/known_hosts:1177
debug3: load_hostkeys: loaded 1 keys from [1.2.3.4]:4321
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:IUUTqOtpUjNSRAOgze0OiVsUoLhm8sgvhTcOtNgFTfe
debug3: put_host_port: [1.2.3.4]:4321
debug3: put_host_port: [1.2.3.4]:4321
debug3: hostkeys_foreach: reading file "/home/user1/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/user1/.ssh/known_hosts:1177
debug3: load_hostkeys: loaded 1 keys from [1.2.3.4]:4321
debug3: hostkeys_foreach: reading file "/home/user1/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/user1/.ssh/known_hosts:1177
debug3: load_hostkeys: loaded 1 keys from [1.2.3.4]:4321
debug1: Host '[1.2.3.4]:4321' is known and matches the ECDSA host key.
debug1: Found key in /home/user1/.ssh/known_hosts:1177
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/user1/.ssh/privatekey explicit
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic
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: Trying private key: /home/user1/.ssh/privatekey
Enter passphrase for key '/home/user1/.ssh/privatekey':
debug3: sign_and_send_pubkey: RSA SHA256:y1HxyI+tlh1DfEuWDjLHLOSUGXo44YzNnrBSrxFh7vG
debug3: sign_and_send_pubkey: signing using rsa-sha2-512
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to 1.2.3.4 ([1.2.3.4]:4321).
debug2: fd 4 setting O_NONBLOCK
debug3: fd 5 is O_NONBLOCK
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting [email protected]
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x20
debug2: client_session2_setup: id 0
debug1: Sending subsystem: sftp
debug2: channel 0: request subsystem confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: subsystem request accepted on channel 0
debug2: Remote version: 3
debug2: Server supports extension "[email protected]" revision 1
debug2: Server supports extension "[email protected]" revision 2
debug2: Server supports extension "[email protected]" revision 2
debug2: Server supports extension "[email protected]" revision 1
debug2: Server supports extension "[email protected]" revision 1
Connected to [email protected].
debug3: Sent message fd 3 T:16 I:1
debug3: SSH_FXP_REALPATH . -> / size 0
sftp>
与之前的连接不同，我们能够获得目标系统上运行的 OpenSSH 版本，然后就可以开始比赛了。
根据提供的信息，有人能告诉我我可能做错了什么吗？我是否缺少客户端上的配置部分，导致我无法连接？问题可能出在目标系统上吗？