The relationship between vsFTPd servers, firewalls, and SELINUX is ambiguous.

Article Title: The relationship between vsFTPd servers and firewalls and SELINUX is ambiguous. Linux is a technology channel of the IT lab in China. Some basic categories include desktop applications, Linux system management, kernel research, embedded systems, and open-source systems. I have seen some brothers on the forum that vsFTPd servers are running normally, but it cannot be accessed or files cannot be uploaded by users. I think it should be a firewall or SELINUX. The FTPD server may be protected by the firewall or SELINUX security mechanism. Therefore, you must have the firewall over ftp, and SELINUX over the ftp server;
In Fedora/Redhat/CentOS, you need to set up a firewall, you can turn off the firewall, or in the custom, let the ftp "through" firewall;
[Root @ localhost ~] # System-config-securitylevel-tui
Or run the following command to clear firewall rules (common );
[Root @ localhost beinan] # iptables-F
The explanation of SELINUX server may be difficult for veteran or novice users. We recommend that you use SELINUX or allow the vsFTPd server to skip SELINUX startup; that is to say, the general method of 4.1 and vsFTPd server startup and shutdown is required; this is effective in Fedora/Redhat/CentOS to start vsFTPd server;
Of course, you can also disable SELINUX. The configuration file in/etc/selinux/config is as follows;
/Etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX = can take one of these three values:
# Enforcing-SELinux security policy is enforced.
# Permissive-SELinux prints warnings instead of enforcing.
# Disabled-SELinux is fully disabled.
SELINUX = Disabled # in this way, The SELINUX server is turned off. restart the system;
# SELINUXTYPE = type of policy in use. Possible values are:
# Targeted-Only targeted network daemons are protected.
# Strict-Full SELinux protection.
SELINUXTYPE = targeted
The article shows that the relationship between vsFTPd servers and firewalls and SELINUX is not bad, but the above method can better handle their relationship.