[root@zzcentos1 ~]#iptables-save > /opt/iprule
[root@zzcentos1 ~]#cat /opt/iprule
# Generated by iptables-save v1.4.21 on Sun Feb 18 18:32:36 2024
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [59:4744]
-A INPUT -s 192.168.246.0/24 -j ACCEPT
-A INPUT -s 192.168.246.0/24 -p icmp -j DROP
COMMIT
# Completed on Sun Feb 18 18:32:36 2024
[root@zzcentos1 ~]#iptables -F
[root@zzcentos1 ~]#iptables -vnL
Chain INPUT (policy ACCEPT 20 packets, 1168 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 11 packets, 908 bytes)
 pkts bytes target     prot opt in     out     source               destination         
[root@zzcentos1 ~]#iptables-restore < /opt/iprule
[root@zzcentos1 ~]#iptables -vnL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   45  2888 ACCEPT     all  --  *      *       192.168.246.0/24     0.0.0.0/0           
    0     0 DROP       icmp --  *      *       192.168.246.0/24     0.0.0.0/0           

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 36 packets, 2760 bytes)
 pkts bytes target     prot opt in     out     source               destination         
[root@zzcentos1 ~]#

①防火墙iptables规则保存

让防火墙规则在开机后自动运行

方法一：

方法二：

开机自动加载规则

第一种：个性化设置放到用户家目录下的配置文件~/.bashrc

第二种：放到全局配置文件中，/etc/profile中，对所有用户生效

第三种：放到开机自启的最后一项，加载系统服务的配置文件中，可以让系统重启即可生效

综上所述，建议放在系统自带的配置/etc/rc.d/rc.local中

②使用iptables-services软件来进行规则的保存和加载（不建议使用）

[root@centos7 ~]#yum -y install iptables-services
[root@centos7 ~]#cp /etc/sysconfig/iptables{,.bak}
#保存现在的规则到文件中方法1
[root@centos7 ~]#/usr/libexec/iptables/iptables.init save
#保存现在的规则到文件中方法2
[root@centos7 ~]#iptables-save > /etc/sysconfig/iptables
#开机启动
[root@centos7 ~]#systemctl enable iptables.service    
[root@centos7 ~]#systemctl mask firewalld.service nftables.service

[root@zzcentos1 ~]#cp /etc/sysconfig/iptables{,.bak}
[root@zzcentos1 ~]#cd /etc/sysconfig/
[root@zzcentos1 sysconfig]#ls
anaconda    crond             iptables.bak     netconsole       rdisc          selinux
atd         ebtables-config   iptables-config  network          readonly-root  smartmontools
authconfig  fcoe              irqbalance       network-scripts  rpcbind        sshd
autofs      firewalld         kdump            nfs              rpc-rquotad    sysstat
cbq         grub              kernel           ntpd             rsyncd         sysstat.ioconf
cgred       init              ksm              ntpdate          rsyslog        virtlockd
chronyd     ip6tables         libvirtd         qemu-ga          run-parts      virtlogd
console     ip6tables-config  man-db           radvd            samba          wpa_supplicant
cpupower    iptables          modules          raid-check       saslauthd
[root@zzcentos1 sysconfig]#iptables-save > /etc/sysconfig/iptables
[root@zzcentos1 sysconfig]#systemctl enable iptables.service
Created symlink from /etc/systemd/system/basic.target.wants/iptables.service to /usr/lib/systemd/system/iptables.service.
[root@zzcentos1 sysconfig]#reboot

二、自定义链

[root@localhost ~]#iptables -t filter -N WEB
##指定是在filter下面添加WEB链，不写默认是filter

1.添加自定义链

一般链是大写

2.给自定义链添加规则

[root@zzcentos1 ~]#iptables -A WEB -p tcp -m multiport --dport 80,443 -j ACCEPT
[root@zzcentos1 ~]#iptables -I WEB -s 192.168.246.8 -p tcp --dport 80 -j DROP

随意添加两条规则

3.使用自定义链

当有流量经过时，进入INPUT链时，会去自定义链WEB中匹配规则

这样优点：可以把相同规则放在一起，方便管理

4.删除自定义链

[root@zzcentos1 ~]#iptables -X WEB
iptables: Too many links.
[root@zzcentos1 ~]#iptables -F WEB
[root@zzcentos1 ~]#iptables -vnL
Chain INPUT (policy ACCEPT 8 packets, 488 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   92  6417 WEB        all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 5 packets, 460 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain WEB (1 references)
 pkts bytes target     prot opt in     out     source               destination         
[root@zzcentos1 ~]#iptables -F INPUT
[root@zzcentos1 ~]#
[root@zzcentos1 ~]#iptables -X WEB
[root@zzcentos1 ~]#iptables -vnL
Chain INPUT (policy ACCEPT 8 packets, 488 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 5 packets, 460 bytes)
 pkts bytes target     prot opt in     out     source               destination         
[root@zzcentos1 ~]#