首先修改 /etc/ssh/sshd_config 文件中的 Port。修改前一定要备份

可以同时启用多个Port所以最好先追加一个端口，新端口校验没问题之后再把原端口删除

防火墙设置

# 永久开放端口
sudo firewall-cmd --zone=public --add-port=3000/tcp --permanent
# 重新加载文件
sudo firewall-cmd --reload
# 永久关闭端口
sudo firewall-cmd --remove-port=3000/tcp --permanent
# 关闭防火墙
sudo systemctl stop firewalld

修改端口号之后，重启sshd服务一直无法成功，把selinux关闭就行了

# 临时关闭
setenforce 0
# 临时打开
setenforce 1

# 永久关闭修改 /etc/selinux/config文件
# 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.
####    修改这个位置 SELINUX 为 disabled 禁用 enforcing 启用
SELINUX=enforcing 
####
# SELINUXTYPE= can take one of three values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected.
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted