CentOS中的防火墙基本区别
CentOS7防火墙名称是：Firewalld （在下使用的系统便是：CentOS7）
7以下版本名字是：Netfilter
请谨记：Iptables 它仅仅只是一个操作防火墙的工具！
在测试环境中，请把SELinux，Firewalld关闭后，Windows即可访问Vsftpd
传说有一些大神，通过Firewalld把Vsftpd的服务端口加入防火墙中，意味着防火墙是开启的状态，Windows也能够直接去访问。在下对防火墙了解不祥，请参考书籍或视频进行了解！
新手硬知识点：Linux安装完Vsftpd后，可以先不去碰Vsftpd的配置文件.它在默认的情况下，可以使用匿名用户登入。
(前提条件：需要关闭SELinux，Firewalld），
案发现场：
[root@localhost ~]# systemctl status vsftpd
â vsftpd.service - Vsftpd ftp daemon
Loaded: loaded (/usr/lib/systemd/system/vsftpd.service; enabled; vendor prese t: disabled)
Active: active (running) since å -----> Vsftpd running
2018-04-28 23:07:05 CST; 3 days ago
Process: 1006 ExecStart=/usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf (code=exited, status=0/SUCCESS)
Main PID: 1025 (vsftpd)
CGroup: /system.slice/vsftpd.service
ââ1025 /usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf
4æ 28 23:07:04 localhost.localdomain systemd[1]: Starting Vsftpd ftp daemon...
4æ 28 23:07:05 localhost.localdomain systemd[1]: Started Vsftpd ftp daemon.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# LANG=C
[root@localhost ~]# systemctl status firewalld
* firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2018-04-28 23:07:01 CST; 3 days ago ------>Firewalld running
Docs: man:firewalld(1)
Main PID: 697 (firewalld)
CGroup: /system.slice/firewalld.service
`-697 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
Apr 28 23:07:00 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
Apr 28 23:07:01 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: ICMP type 'beyond-scope' is not supported by the kernel for ipv6.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: beyond-scope: INVALID_ICMPTYPE: No supported ICMP type., ign...time.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: ICMP type 'failed-policy' is not supported by the kernel for ipv6.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: failed-policy: INVALID_ICMPTYPE: No supported ICMP type., ig...time.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: ICMP type 'reject-route' is not supported by the kernel for ipv6.
Apr 28 23:07:01 localhost.localdomain firewalld[697]: WARNING: reject-route: INVALID_ICMPTYPE: No supported ICMP type., ign...time.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# systemctl stop firewalld ---->stop firewalld
[root@localhost ~]#
以上，便是在下学习Linux的时候记录，如有不正之处，请与在下联系！
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