临时
#echo "1" > /proc/sys/net/ipv4/ip_forward
永久
#vi /etc/sysctl.conf
net.ipv4.ip_forward = 0
 =》 
net.ipv4.ip_forward = 1
#sysctl -p



#service iptables restart
#iptables -t nat -F
#iptables -F


#vi /etc/iptables.firewall

*nat
:PREROUTING ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A POSTROUTING -j MASQUERADE
-A PREROUTING  -d 172.16.67.143/32 -p tcp -m tcp --dport 5432 -j DNAT --to-destination 172.16.67.140:5432
-A POSTROUTING  -s 172.16.67.140/32 -p tcp -m tcp --sport 5432 -j SNAT --to-source 172.16.67.143 
COMMIT



#iptables-restore < /etc/iptables.firewall 


#service iptables save