CentOS 6和7版本环境安装Fail2ban服务来防止暴力破解FTP/SSH

如果出于各种少折腾的需求，如果能不用VPS尽量我们建站的时候就不要用VPS，因为在很多时候我们会受到来自各种主动与非主动的攻击问题出现。一旦出现问题，我们就需要花费大量的时间和精力去解决这样的问题。刚才在寻找是否有些教程可以写的时候看到这篇关于Fail2ban应用文章，于是也就整理过来分享。

基于CentOS 6或者7版本的系统，我们可以安装Fail2ban工具来阻止一定的暴力破解SSH或者FTP账户问题，也许不能足够的解决问题，但至少可以解决一般的问题。

第一、Fail2ban安装

A – CentOS 6

rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
yum install fail2ban

B – CentOS 7

rpm -Uvh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-2.noarch.rpm
yum install fail2ban

选择对应的系统进行脚本一键安装，在安装过程中会出现三次是否需要输入Y的步骤，我们输入y且回车继续到最后。

第二、Fail2ban设置

编辑/etc/fail2ban/jail.conf文件，我们需要设置Fail2ban配置文件。

[DEFAULT]

# \”ignoreip\” can be an IP address, a CIDR mask or a DNS host. Fail2ban will not
# ban a host which matches an address in this list. Several addresses can be
# defined using space separator.

ignoreip = 127.0.0.1/8

# External command that will take an tagged arguments to ignore, e.g. ,
# and return true if the IP is to be ignored. False otherwise.
#
# ignorecommand = /path/to/command

ignorecommand =

# \”bantime\” is the number of seconds that a host is banned.

bantime  = 600

# A host is banned if it has generated \”maxretry\” during the last \”findtime\”
# seconds.

findtime  = 600

# \”maxretry\” is the number of failures before a host get banned.

maxretry = 3

# \”backend\” specifies the backend used to get files modification.
# Available options are \”pyinotify\”, \”gamin\”, \”polling\” and \”auto\”.
# This option can be overridden in each jail as well.
#
# pyinotify: requires pyinotify (a file alteration monitor) to be installed.
#              If pyinotify is not installed, Fail2ban will use auto.
# gamin:     requires Gamin (a file alteration monitor) to be installed.
#              If Gamin is not installed, Fail2ban will use auto.
# polling:   uses a polling algorithm which does not require external libraries.
# auto:      will try to use the following backends, in order:
#              pyinotify, gamin, polling.

backend = auto

# \”usedns\” specifies if jails should trust hostnames in logs,
#   warn when DNS lookups are performed, or ignore all hostnames in logs
#
# yes:   if a hostname is encountered, a DNS lookup will be performed.
# warn:  if a hostname is encountered, a DNS lookup will be performed,
#        but it will be logged as a warning.
# no:    if a hostname is encountered, will not be used for banning,
#        but it will be logged as info.

usedns = warn

一般，我们设置这几个就可以，具体的含义如下：

ignoreip = 127.0.0.1 #忽略的IP列表,不受设置限制（白名单）
bantime = 600 #屏蔽时间，单位：秒
findtime = 600 #这个时间段内超过规定次数会被ban掉
maxretry = 3 #最大尝试次数
backend = auto #日志修改检测机制（gamin、polling和auto这三种）
[ssh-iptables] #针对各服务的检查配置，如设置bantime、findtime、maxretry和全局冲突，服务优先级大于全局设置
enabled = true #是否激活此项（true/false）
filter = sshd #过滤规则filter的名字，对应filter.d目录下的sshd.conf
action = iptables[name=SSH, port=ssh, protocol=tcp] #动作的相关参数
sendmail-whois[name=SSH, dest=root, [email protected]] #触发报警的收件人
logpath = /var/log/secure #检测的系统的登陆日志文件
maxretry = 5 #最大尝试次数

第三、启动fail2ban

CentOS 6:
service fail2ban restart
CentOS 7:
systemctl restart fail2ban.service

第四、设置开机启动

CentOS 6:
chkconfig fail2ban on
CentOS 7:
systemctl enable fail2ban

总结，这样我们就在自己的VPS中启动和设置Fail2ban设置，可以稍微的防护短暂的IP重复尝试的访问我们的VPS然后给予限制的手段。当然，一般我们正常的网站，如果不去招惹别人，一般别人也不会太无聊的。