问题描述：
CentOS7.5 修改默认ssh端口号,重启sshd失败如何解决
重启sshd时 :
解决方案：
1.关闭setenforce
setenforce 0
设置永久关闭selinux
vim /etc/sysconfig/selinux
将第7行内容修改如下
SELINUX=disabled
# 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 - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted
2.启动sshd服务
systemctl start sshd
3.查看sshd服务状态
systemctl status sshd
4.防火墙开放sshd端口
firewall-cmd --zone=public --add-port=2023/tcp --permanent
firewall-cmd --reload
systemctl restart sshd