xshell突然连接不上-报错：Socket error Event: 32 Error: 10053. Connection closing...Socket close.

我的阿里云服务器今天突然连接不上

在xshel连接报错：
 

Connecting to 39.100.144.30:22...
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.

Socket error Event: 32 Error: 10053.
Connection closing...Socket close.

Connection closed by foreign host.

Disconnected from remote host(39.100.144.30) at 09:55:41.

Type `help' to learn how to use Xshell prompt.

 

在终端登录查看信息

# service sshd status
sshd[7794]: Failed password for invalid user admin from 45.224.105.95 port 42423 ssh2
sshd[10205]: Invalid user sniffer from 123.21.253.168 port 60809
sshd[10205]: error: Could not get shadow information for NOUSER
sshd[10205]: Failed password for invalid user sniffer from 123.21.253.168 port 60809 ssh2
sshd[24284]: Invalid user admina from 14.187.177.87 port 56323
sshd[24284]: error: Could not get shadow information for NOUSER
sshd[24284]: Failed password for invalid user admina from 14.187.177.87 port 56323 ssh2
sshd[25822]: Accepted password for root from 47.96.60.110 port 2099 ssh2
sshd[25827]: Accepted password for root from 47.96.60.213 port 37498 ssh2
sshd[25847]: Accepted password for root from 47.96.60.214 port 14030 ssh2

 

查看日志

# cat /var/log/messages |grep error
 sshd[598]: error: kex_exchange_identification: Connection closed by remote host
 sshd[2747]: error: kex_exchange_identification: Connection closed by remote host
 sshd[27038]: error: kex_exchange_identification: Connection closed by remote host
 sshd[7787]: error: Could not get shadow information for NOUSER
 sshd[7794]: error: Could not get shadow information for NOUSER
 sshd[29152]: error: kex_exchange_identification: Connection closed by remote host
 sshd[10205]: error: Could not get shadow information for NOUSER
 sshd[11128]: error: kex_exchange_identification: read: Connection reset by peer
 sshd[12179]: error: kex_exchange_identification: Connection closed by remote host
 sshd[23249]: error: kex_exchange_identification: Connection closed by remote host
 sshd[24281]: error: kex_exchange_identification: Connection closed by remote host
 sshd[24284]: error: Could not get shadow information for NOUSER
 sshd[25067]: error: kex_exchange_identification: Connection closed by remote host
 sshd[25076]: error: kex_exchange_identification: Connection closed by remote host
 sshd[26628]: error: kex_exchange_identification: Connection closed by remote host

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes

最后查出是网络的问题。连接手机热点就可以登录服务器。【抓狂】

 

中间鬼使神差的，重启sshd服务，重启服务器，重置密码导致在云控制台登录时出现以下情况

解决：/etc/ssh/sshd_config配置文件中  #UsePAM no  参数去掉 #号  ，重启sshd服务后好了，

 

好在ssh不能连接时，还可以用VNC连接。

之后为了确认是否是这个参数影响的，做好快照后，又把参数 #UsePAM no   的#号加上了，重启sshd服务后，依旧可以用ssh方式登录，此时我就有些摸不着头脑了？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？

UsePAM是的openssh中的一个pam证书验证模块，默认是启用的

网上有些是因为启用了pam导致登录失败

有些是因为没有启用登录失败

不懂啊！！！全网 唯一 一篇对于PAM的介绍 《保护ssh的三把锁》【反正公子这么认为】

 

• 总结检查思路

1、更换网络再次登录测试【强烈推荐首先尝试】

2、selinux机制是否关闭【确认已经关闭】

3、检查/etc/ssh/sshd_config配置文件中  #UsePAM no