日记 [2007年01月24日]服务器加强安全2 防火墙iptable配置

查询系统是否安装iptables（默认安装）
rpm -q iptables

[b]vi /etc/syslog.conf[/b]
编辑添加如下内容
#IPTables logging
# kernel messages.
kern.debug;kern.info /var/log/firewal
重启syslog服务
/etc/rc.d/init.d/syslog restart
insmod ip_conntrack_ftp（加载ftp模块）
建立防火墙脚本
vi /root/primary_firewall
#The NAT portion of the ruleset. Used for Network Address Transalation.
#Usually not needed on a typical web server, but it's there if you need it.
*nat
:PREROUTING ACCEPT [127173:7033011]
:POSTROUTING ACCEPT [31583:2332178]
:OUTPUT ACCEPT [32021:2375633]
COMMIT
#The Mangle portion of the ruleset. Here is where unwanted packet types get dropped.
#This helps in making port scans against your server a bit more time consuming and difficult, but not impossible.
*mangle
:PREROUTING ACCEPT [444:43563]
:INPUT ACCEPT [444:43563]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [402:144198]
:POSTROUTING ACCEPT [402:144198]
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
COMMIT
#The FILTER section of the ruleset is where we initially drop all packets and then selectively open certain ports.
#We will also enable logging of all dropped requests.
*filter
:INPUT DROP [1:242]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
:LOG_DROP - [0:0]
:LOG_ACCEPT - [0:0]
:icmp_packets - [0:0]
#First, we cover the INPUT rules, or the rules for incoming requests.
#Note how at the end we log any incoming packets that are not accepted.
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 20 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 21 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j LOG_ACCEPT
-A INPUT -p tcp -m tcp --dport 25 -j LOG_ACCEPT
-A INPUT -p tcp -m tcp --dport 43 -j ACCEPT
-A INPUT -p udp -m udp --dport 53 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 110 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 143 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
#uncomment the next line if you are running Spamassassin on your server
#-A INPUT -p tcp -m tcp --dport 783 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 993 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A INPUT -s 127.0.0.1 -j ACCEPT
-A INPUT -p icmp -j icmp_packets
-A INPUT -j LOG_DROP
#Next, we cover the OUTPUT rules, or the rules for all outgoing traffic.
#Note how at the end we log any outbound packets that are not accepted.
-A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 20 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 21 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 23 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 25 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 43 -j ACCEPT
-A OUTPUT -p udp -m udp --dport 53 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 110 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 143 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 443 -j ACCEPT
#uncomment the next line if you are running Spamassassin on your server
#-A OUTPUT -p tcp -m tcp --dport 783 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 993 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A OUTPUT -d 127.0.0.1 -j ACCEPT
-A OUTPUT -p icmp -j icmp_packets
-A OUTPUT -j LOG_DROP
#Here we have 2 sets of logging rules. One for dropped packets to log all dropped requests and one for accepted packets, should we wish to log any accepted requesets.
-A LOG_DROP -j LOG --log-prefix "[IPTABLES DROP] : " --log-tcp-options --log-ip-options
-A LOG_DROP -j DROP
-A LOG_ACCEPT -j LOG --log-prefix "[IPTABLES ACCEPT] : " --log-tcp-options --log-ip-options
-A LOG_ACCEPT -j ACCEPT
#And finally, a rule to deal with ICMP requests. We drop all ping requests except from our own server.
# 用服务器IP替换1.2.3.4
-A icmp_packets -p icmp -m icmp --icmp-type 0 -j ACCEPT
-A icmp_packets -s 1.2.3.4 -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A icmp_packets -p icmp -m icmp --icmp-type 8 -j DROP
-A icmp_packets -p icmp -m icmp --icmp-type 3 -j ACCEPT
-A icmp_packets -p icmp -m icmp --icmp-type 11 -j ACCEPT
COMMIT
执行防火墙脚本
iptables-restore < /root/primary_firewall
不报错说明防火墙脚本已经刷新
iptables -L查看防火墙状态
测试防火墙
nmap 防火墙IP
可以看到防火墙打开的端口
以上一个简单的防火墙就配置好了，要更好的使用，我们需要分析防火墙日志
安装iptables日志分析工具
tar zxvf iptables_logger_v0.4.tar.gz
cd iptables
mysql -u root -p
mysql> create database iptables;
建立访问数据库的用户iptables_admin和iptables_user
mysql> grant all privileges on iptables.* to iptables_admin@localhost identified by '密码';
mysql> grant all privileges on iptables.* to iptables_user@localhost identified by '密码';
mysql> quit
导入数据库
cat sql/db.sql | mysql -u iptables_admin -p iptables
安装web界面
cp -R web /var/www/html/firewalll
修改配置文件中密码的设置
vi /var/www/html/firewall/config.php
# Password of the MySQL database
#Make sure you enter your "iptables_user" password in place of the red x's below
$db_password="xxxxxx";
vi scripts/feed_db.pl
my $dsn = 'DBI:mysql:iptables:localhost';
my $db_user_name = 'iptables_admin';
my $db_password = 'xxxxx';
my $log_file = '/var/log/firewall';
my $pid_file = "/var/run/iptablelog.pid";
cp scripts/feed_db.pl /usr/local/bin/
iptablelog加入到开机自启动
cp scripts/iptablelog /etc/rc.d/init.d/
/etc/init.d/iptablelog start
从浏览器访问 http://www.yourdomain.com/firewall
可以看到iptables的界面

开机启动防火墙


cp /root/primary_firewall /etc/sysconfig/iptables
vi /etc/rc.local
添加下列行
/sbin/insmod ip_conntrack_ftp
不过我的机器似乎没有这个模块