kex_exchange_identification：远程主机关闭连接

Question

尝试通过跳转服务器连接到在 Centos 7 上运行的 Web 服务器，以前此连接工作正常，没有任何问题，但现在不确定出了什么问题。

以下是状态

$ ssh -vvv abc@JUMP_SERVER_IP -J 10.10.0.5 -i .ssh/id_rsa_iit
OpenSSH_8.2p1 Ubuntu-4ubuntu0.2, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname JUMP_SERVER_IP is address
debug1: Setting implicit ProxyCommand from ProxyJump: ssh -vvv -W '[%h]:%p' 10.10.0.5
debug1: Executing proxy command: exec ssh -vvv -W '[JUMP_SERVER_IP]:22' 10.10.0.5
debug1: identity file .ssh/id_rsa_iit type 0
debug1: identity file .ssh/id_rsa_iit-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.2
OpenSSH_8.2p1 Ubuntu-4ubuntu0.2, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 10.10.0.5 is address
debug2: ssh_connect_direct
debug1: Connecting to 10.10.0.5 [10.10.0.5] port 22.
debug1: connect to address 10.10.0.5 port 22: Connection timed out
ssh: connect to host 10.10.0.5 port 22: Connection timed out
kex_exchange_identification: Connection closed by remote host