Linux防火墙主要用于控制网络流量，保护系统安全。在Linux中，有几种不同的防火墙管理工具，其中最常见的是
iptables和firewalld。本章主要讲述如何关闭防火墙。
操作系统：
CentOS Stream 9
操作步骤：
关闭防火墙，selinux ,22行 SELINUX=disabled
[root@localhost ~]# cat -n /etc/sysconfig/selinux1 2 # This file controls the state of SELinux on the system.3 # SELINUX= can take one of these three values:4 # enforcing - SELinux security policy is enforced.5 # permissive - SELinux prints warnings instead of enforcing.6 # disabled - No SELinux policy is loaded.7 # See also:8 # https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/using_selinux/changing-selinux-states-and-modes_using-selinux#changing-selinux-modes-at-boot-time_changing-selinux-states-and-modes9 #10 # NOTE: Up to RHEL 8 release included, SELINUX=disabled would also11 # fully disable SELinux during boot. If you need a system with SELinux12 # fully disabled instead of SELinux running with no policy loaded, you13 # need to pass selinux=0 to the kernel command line. You can use grubby14 # to persistently set the bootloader to boot with selinux=0:15 #16 # grubby --update-kernel ALL --args selinux=017 #18 # To revert back to SELinux enabled:19 #20 # grubby --update-kernel ALL --remove-args selinux21 #22 SELINUX=disabled 此处注意23 # SELINUXTYPE= can take one of these three values:24 # targeted - Targeted processes are protected,25 # minimum - Modification of targeted policy. Only selected processes are protected.26 # mls - Multi Level Security protection.27 SELINUXTYPE=targeted28
29
[root@localhost ~]# cat -n /etc/selinux/config1 2 # This file controls the state of SELinux on the system.3 # SELINUX= can take one of these three values:4 # enforcing - SELinux security policy is enforced.5 # permissive - SELinux prints warnings instead of enforcing.6 # disabled - No SELinux policy is loaded.7 # See also:8 # https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/using_selinux/changing-selinux-states-and-modes_using-selinux#changing-selinux-modes-at-boot-time_changing-selinux-states-and-modes9 #10 # NOTE: Up to RHEL 8 release included, SELINUX=disabled would also11 # fully disable SELinux during boot. If you need a system with SELinux12 # fully disabled instead of SELinux running with no policy loaded, you13 # need to pass selinux=0 to the kernel command line. You can use grubby14 # to persistently set the bootloader to boot with selinux=0:15 #16 # grubby --update-kernel ALL --args selinux=017 #18 # To revert back to SELinux enabled:19 #20 # grubby --update-kernel ALL --remove-args selinux21 #22 SELINUX=disabled #注意23 # SELINUXTYPE= can take one of these three values:24 # targeted - Targeted processes are protected,25 # minimum - Modification of targeted policy. Only selected processes are protected.26 # mls - Multi Level Security protection.27 SELINUXTYPE=targeted28
29 firewalld
[root@localhost ~]# systemctl disable firewalld
[root@localhost ~]#
[root@localhost ~]#
[root@localhost ~]#
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# 重启服务器
[root@localhost ~]#reboot查询防火墙是否关闭
[root@localhost ~]# sestatus
SELinux status: disabled
[root@localhost ~]# systemctl status firewalld
○ firewalld.service - firewalld - dynamic firewall daemonLoaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; preset: >Active: inactive (dead)Docs: man:firewalld(1)
[root@localhost ~]# iptables -vnL
Chain INPUT (policy ACCEPT 0 packets, 0 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 0 packets, 0 bytes)pkts bytes target prot opt in out source destination
[root@localhost ~]#