我在 TP Link 路由器后面有一台 CentOS 7.5 机器。
我已在路由器中启用端口转发（并重新启动）。
然而，由于某种原因，我可以 ping 通路由器，但无法通过端口 22 telnet 或 ssh 到该机器。
$ telnet [public IP] 22
Trying [public IP]...
telnet: connect to address [public IP]: Connection refused
$ ssh root@[public IP]
ssh: connect to host [public IP] port 22: Connection refused
我也尝试了另一个用户，但得到的结果是一样的。
我确实停止了firewall.d：
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Tue 2018-05-22 10:20:42 CST; 4min 26s ago
Docs: man:firewalld(1)
Process: 733 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=0/SUCCESS)
Main PID: 733 (code=exited, status=0/SUCCESS)
May 21 00:49:14 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
May 21 00:49:14 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
May 22 10:20:41 localhost.localdomain systemd[1]: Stopping firewalld - dynamic firewall daemon...
May 22 10:20:42 localhost.localdomain systemd[1]: Stopped firewalld - dynamic firewall daemon.
我确实暂时禁用了 SELinux：
[root@localhost ~]# setenforce 0
[root@localhost ~]# sestatus
SELinux status: enabled
SELinuxfs mount: /sys/fs/selinux
SELinux root directory: /etc/selinux
Loaded policy name: targeted
Current mode: permissive
Mode from config file: enforcing
Policy MLS status: enabled
Policy deny_unknown status: allowed
Max kernel policy version: 31
sshd 确实正在运行：
[root@localhost ~]# systemctl status sshd
● sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2018-05-22 10:42:03 CST; 8min ago
Docs: man:sshd(8)
man:sshd_config(5)
Main PID: 11861 (sshd)
Tasks: 1
CGroup: /system.slice/sshd.service
└─11861 /usr/sbin/sshd -D
May 22 10:42:03 localhost.localdomain systemd[1]: Starting OpenSSH server daemon...
May 22 10:42:03 localhost.localdomain sshd[11861]: Server listening on :: port 22.
May 22 10:42:03 localhost.localdomain sshd[11861]: Server listening on 0.0.0.0 port 22.
May 22 10:42:03 localhost.localdomain systemd[1]: Started OpenSSH server daemon.
任何想法？