安装iptables服务：

  apt-get install iptables-persisten
  在安装过程中选择两次yes，即可

查看netfilter-persistent服务是否在运行

  systemctl status netfilter-persistent
  ● netfilter-persistent.service - netfilter persistent configuration
     Loaded: loaded (/lib/systemd/system/netfilter-persistent.service; enabled; vendor preset: enabled)
     Active: active (exited) since Tue 2023-02-28 14:02:21 CST; 13min ago
    Process: 251 ExecStart=/usr/sbin/netfilter-persistent start (code=exited, status=0/SUCCESS)
   Main PID: 251 (code=exited, status=0/SUCCESS)
  ​
  Feb 28 14:02:21 forlinx systemd[1]: Starting netfilter persistent configuration...
  Feb 28 14:02:21 forlinx netfilter-persistent[251]: run-parts: executing /usr/share/netfilter-persistent/plugins.d/15-ip4tables start
  Feb 28 14:02:21 forlinx netfilter-persistent[251]: run-parts: executing /usr/share/netfilter-persistent/plugins.d/25-ip6tables start
  Feb 28 14:02:21 forlinx systemd[1]: Started netfilter persistent configuration.

设置转发服务并实现持久化：

  
  root@forlinx:~# iptables -t nat -A POSTROUTING -o eno0 -j MASQUERADE
  root@forlinx:~# netfilter-persistent save
  run-parts: executing /usr/share/netfilter-persistent/plugins.d/15-ip4tables save
  run-parts: executing /usr/share/netfilter-persistent/plugins.d/25-ip6tables save

对比前后配置文件的变化：

前：

  
  root@forlinx:~# cat rules.v4_old 
  # Generated by iptables-save v1.6.1 on Tue Feb 28 13:57:40 2023
  *nat
  :PREROUTING ACCEPT [543:72796]
  :INPUT ACCEPT [324:37885]
  :OUTPUT ACCEPT [77:3640]
  :POSTROUTING ACCEPT [77:3640]
  :DOCKER - [0:0]
  -A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER
  -A OUTPUT ! -d 127.0.0.0/8 -m addrtype --dst-type LOCAL -j DOCKER
  -A POSTROUTING -s 172.17.0.0/16 ! -o docker0 -j MASQUERADE
  -A DOCKER -i docker0 -j RETURN
  COMMIT
  # Completed on Tue Feb 28 13:57:40 2023
  # Generated by iptables-save v1.6.1 on Tue Feb 28 13:57:40 2023
  *mangle

后：

  
  root@forlinx:~# cat /etc/iptables/rules.v4
  # Generated by iptables-save v1.6.1 on Tue Feb 28 14:35:31 2023
  *nat
  :PREROUTING ACCEPT [71:8088]
  :INPUT ACCEPT [52:5026]
  :OUTPUT ACCEPT [6:214]
  :POSTROUTING ACCEPT [5:145]
  :DOCKER - [0:0]
  -A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER
  -A OUTPUT ! -d 127.0.0.0/8 -m addrtype --dst-type LOCAL -j DOCKER
  -A POSTROUTING -s 172.17.0.0/16 ! -o docker0 -j MASQUERADE
  -A POSTROUTING -o eno0 -j MASQUERADE
  -A DOCKER -i docker0 -j RETURN
  ......

可以发现在执行iptables持久化之后，增加了一条命令