Linux ssh connection

1. 确定可以ping通linux服务器；

2. 确定可以telnet通linux服务器22端口；

local check port status: netstat -antup

如果不同，或者修改防火墙规则；或者选择关闭防火墙。/etc/init.d/iptables stop

3. 修改ssh配置文件/etc/ssh/sshd_config

a. 原文：#PermitRootLogin yes
修改成：PermitRootLogin yes

b. 原文：UseDNS yes

修改成：UseDNS no

修改完成后重启sshd服务：service sshd restart

Additional:

If the port is not the default port,

ssh <IP address> -p <port>

SSH hang after authoration successful

reason: manually error remove the # for the "ForceCommand cvs server" Line

Prevent user login by ssh

Mehod 1

1. add /etc/ssh/sshd_config file with following context

Denyusers <user name>

2. Restart the ssh service

service sshd restart

Method 2

1. Create user with command: useradd -s /sbin/nologin <new username>

2. change user with usermod -s /sbin/nologin <username >

Devops Engineer