概述
由于需要开放telnet非默认端口，添加SElinux规则时报错。
[root@localhost ~]# semanage port -a -t telnetd_port_t -p tcp 23023
SELinux: Could not downgrade policy file /etc/selinux/targeted/policy/policy.24, searching for an older version.
SELinux: Could not open policy file <= /etc/selinux/targeted/policy/policy.24: No such file or directory
libsemanage.semanage_reload_policy: load_policy returned error code 2.
SELinux: Could not downgrade policy file /etc/selinux/targeted/policy/policy.24, searching for an older version.
SELinux: Could not open policy file <= /etc/selinux/targeted/policy/policy.24: No such file or directory
libsemanage.semanage_reload_policy: load_policy returned error code 2.
/usr/sbin/semanage: 无法提交 semanage 事务处理办法
由于semanage命令添加操作是需要SElinux处于开启状态，在关闭状态是无法进行操作的。
[root@localhost ~]# sestatus
SELinux status: disabled
[root@localhost ~]# getenforce
Disabled
# 部分文件位置：/etc/sysconfig/selinux
[root@localhost ~]# sudo vi /etc/selinux/config
SELINUX=enforcing