如何在FreeBSD上设置PF防火墙来保护Web服务器(3)

输入下面这些命令：

# service pflog start
# service pflog stop
# service pflog restart

第四步：pfctl 命令的简单介绍

你需要使用 pfctl 命令来查看 PF 规则集和参数配置，包括来自包过滤器packet filter的状态信息。让我们来看一下所有常见命令：

显示 PF 规则信息

# pfctl -s rules

示例输出：

block return in log all
block drop out all
block drop in quick on ! vtnet0 inet from 172.xxx.yyy.zzz/24 to any
block drop in quick inet from 172.xxx.yyy.zzz/24 to any
pass in quick on vtnet0 inet proto tcp from 139.aaa.ccc.ddd to 172.xxx.yyy.zzz/24 port = ssh flags S/SA keep state label "USER_RULE: Allow SSH from 139.aaa.ccc.ddd"
pass inet proto icmp all icmp-type echoreq keep state
pass out quick on vtnet0 proto tcp from any to any port = domain flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ntp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = smtp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = http flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = https flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ftp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ssh flags S/SA keep state
pass out quick on vtnet0 proto udp from any to any port = domain keep state
pass out quick on vtnet0 proto udp from any to any port = ntp keep state

显示每条规则的详细内容

# pfctl -v -s rules

在每条规则的详细输出中添加规则编号：

# pfctl -vvsr show

显示状态信息

# pfctl -s state
# pfctl -s state | more
# pfctl -s state | grep 'something'

如何在命令行中禁止 PF 服务

# pfctl -d

如何在命令行中启用 PF 服务

# pfctl -e

如何在命令行中刷新 PF 规则/NAT/路由表

# pfctl -F all

示例输出：

rules cleared
nat cleared
0 tables deleted.
2 states cleared
source tracking entries cleared
pf: statistics cleared
pf: interface flags reset

如何在命令行中仅刷新 PF 规则

# pfctl -F rules

如何在命令行中仅刷新队列

# pfctl -F queue

如何在命令行中刷新统计信息（它不是任何规则的一部分）

# pfctl -F info

如何在命令行中清除所有计数器

# pfctl -z clear

第五步：查看 PF 日志

PF 日志是二进制格式的。使用下面这一命令来查看：

# tcpdump -n -e -ttt -r /var/log/pflog

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