CentOS system to modify the SSH telnet port

1. Modify SSH telnet port to 8888
# Vi/etc/ssh/sshd_config

Port 8888 #把 #Port 22 modified to port 8888

# servicesshd Restart #重启SSH服务 or service sshd restart

2. Firewall Add port
The default iptables only part of the port, use additional ports such as 8888 need to add white list in iptables otherwise you will not be able to connect to the SSH server
# iptables-i input-p TCP--dport 8888-j ACCEPT
# iptables-a input-p TCP--dport 8888-j ACCEPT
#service iptables Save
The first command takes effect immediately but is invalidated after reboot, so you need to save the command to the iptables configuration file, path:/etc/sysconfig/iptables,
Saved commands can also be: Iptables-save >/etc/sysconfig/iptables

Some knowledge of iptables:
Centos 6.x iptables open port white list
Linux iptables Shielding or IP
Iptables usage