linux 禁止指定ip訪問

linux中如何禁止指定的ip訪問呢? 
比如被別人暴力破解,被別人使用不同的密碼嘗試登錄

前段時間,我在阿里雲的主機就收到了攻擊,並且被安裝了後門:

所以我想直接禁用這些ip的訪問.怎麼辦呢? 
解決方案:修改配置文件/etc/hosts.deny 
把要禁止ssh訪問的ip都放在/etc/hosts.deny 中: 

配置文件中有ip 117.136.38.47. 
那麼當這個ip嘗試ssh登錄時,就會: 

直接就拒絕登錄了,都不會校驗用戶名和密碼. 
配置文件/etc/hosts.deny 內容:

#
# hosts.deny    This file contains access rules which are used to
#               deny connections to network services that either use
#               the tcp_wrappers library or that have been
#               started through a tcp_wrappers-enabled xinetd.
#
#               The rules in this file can also be set up in
#               /etc/hosts.allow with a 'deny' option instead.
#
#               See 'man 5 hosts_options' and 'man 5 hosts_access'
#               for information on rule syntax.
#               See 'man tcpd' for information on tcp_wrappers
#
sshd:121.42.0.15
sshd:121.42.0.17
sshd:121.42.0.19
sshd:121.42.0.30
sshd:121.42.0.31
sshd:121.42.0.36
sshd:121.15.151.181

使用# 可以註釋 
也支持ip 局部匹配: 

參考:解決阿里雲主機受到攻擊的問題2 
linux 禁止指定ip訪問