开启系统转发功能：

[root@localhost /]# vim /etc/sysctl.conf

# Generated by iptables-save v1.4.7 on Thu May 12 17:31:40 2016
*nat
:OUTPUT ACCEPT [0:0]
:PREROUTING ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING -s 10.0.0.0/24 -o eth0 -j SNAT --to 121.11.76.182
-A PREROUTING -d 121.11.76.132 -p tcp --dport 1801 -j DNAT --to-destination 121.11.76.182:1801
-A POSTROUTING -d 121.11.76.182 -p tcp --dport 1801 -j SNAT --to 121.11.76.132
-A PREROUTING -p tcp -m multiport --dport 4433,2103,2105 -j DNAT --to 121.11.76.182
-A POSTROUTING -j MASQUERADE
COMMIT
# Completed on Thu May 12 17:31:40 2016
# Generated by iptables-save v1.4.7 on Thu May 12 17:31:40 2016
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Thu May 12 17:31:40 2016
# Generated by iptables-save v1.4.7 on Thu May 12 17:31:40 2016
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 6379 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 18888 -j ACCEPT
-A FORWARD -i eth0 -s 121.11.76.182 -p tcp --sport 1801 -j ACCEPT
-A FORWARD -o eth0 -d 121.11.76.182 -p tcp --dport 1801 -j ACCEPT
-A FORWARD -i eth0 -s 121.11.76.182 -p tcp -m multiport --sport 4433,2103,2105 -j ACCEPT
-A FORWARD -o eth0 -d 121.11.76.182 -p tcp -m multiport --dport 4433,2103,2105 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Thu May 12 17:31:40 2016