DenyHosts是用python2.3编写的一个程序，会分析/var/log/secure等文件，当发现同一个ip进行多次ssh登录失败时会将其写入/etc/hosts.dengy文件，达到屏蔽该ip的目的。
下载DenyHosts包
[root@localhost ~]# wget http://jaist.dl.sourceforge.net/project/denyhosts/denyhosts/2.6/DenyHosts-2.6.tar.gz
安装DenyHosts
[root@localhost ~]# tar xf DenyHosts-2.6.tar.gz
[root@localhost ~]# cd DenyHosts-2.6
[root@localhost DenyHosts-2.6]# python setup.py install
制作配置文件
[root@localhost DenyHosts-2.6]# cp denyhosts.cfg-dist /etc/denyhosts.cfg
[root@localhost DenyHosts-2.6]# cp daemon-control-dist daemon-control
[root@localhost DenyHosts-2.6]# chown root daemon-control
[root@localhost DenyHosts-2.6]# chmod 700 daemon-control
修改配置文件
将daemon-control中的#DENYHOSTS_CFG = "/usr/share/denyhosts/denyhosts.cfg"改为 DENYHOSTS_CFG = “/etc/denyhosts.cfg”
启动
[root@localhost DenyHosts-2.6]# ./daemon-control start（注意相对路径）
测试另外一台服务器远程连接172.16.1.16
默认允许五次，测试发现登陆失败五次之后不允许登陆
[root@localhost ~]# ssh abc@172.16.1.16
abc@172.16.1.16's password:
Permission denied, please try again.
abc@172.16.1.16's password:
Permission denied, please try again.
abc@172.16.1.16's password:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
[root@localhost ~]#
......
[root@localhost ~]# ssh abc@172.16.1.16
查看hosts.deny文件
登陆连续失败之后就会把ip地址写在hosts.deny文件。
