我尝试从 Linux 计算机通过 ssh 连接到我们的 HP Procurve 交换机，但收到错误：“ssh_exchange_identification：连接被远程主机关闭。” （也作为根）
我可以通过 ssh 连接到其他 Linux 机器，没有任何问题。通过 Windows + Putty 连接到 Switch 也可以。
它是标准的 Debian 安装，没有任何特定的配置。
我是不是忘记了什么？
-vv 1.0.0.20
OpenSSH_7.4p1 Debian-10+deb9u3, OpenSSL 1.0.2l 25 May 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "1.0.0.20" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 1.0.0.20 [1.0.0.20] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u3
ssh_exchange_identification: Connection closed by remote host
答案1
ssh_exchange_identification: Connection closed by remote host
当 SSH 客户端与服务器建立 TCP 连接时，发生的第一个数据交换是服务器将其版本字符串发送到客户端。您收到的消息表明服务器没有将其版本字符串发送到客户端，而是关闭了 TCP 连接。
这不是身份验证失败。服务器尚未将其主机密钥发送给客户端，并且客户端尚未尝试向服务器进行身份验证。服务器刚刚接受了来自客户端的 TCP 连接，然后就断开了它。
对此行为最简单的解释是，服务器被配置为不接受仅来自某些 IP 地址的连接，而您正尝试从不允许连接到服务器的系统进行连接。