这是因为防火墙的原因，把响应端口开启就行了。
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [:]
:FORWARD ACCEPT [:]
:OUTPUT ACCEPT [:]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT #mysql port
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT #nginx
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT #tomcat
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT #ssh port
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT #vsftpd
-A INPUT -m state --state NEW -m tcp -p tcp --dport : -j ACCEPT
-A OUTPUT -m state --state NEW -m tcp -p tcp --sport : -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT
-A OUTPUT -m state --state NEW -m tcp -p tcp --sport -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport -j ACCEPT
-A OUTPUT -m state --state NEW -m tcp -p tcp --sport -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
二、参考文件